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Cognizant Technical Interview Questions

CTS Technical Interview Questions for Freshers

There is a lot of confusion about Cognizant Technical Interview Questions and Process. Since, they change the process every year. On this page you will find the most updated Information, questions and process for CTS Technical Interview Questions.

Infact, in 2017 95% of the people who are working in Cognizant had prepared from PrepInsta. Yes, you heard it right 95%.

This Dashboard is only for Technical Questions, if you want to study for other sections like Coding Interview Questions or HR Interview Questions and student Interview Experience visit Cognizant Main Interview Dashboard here.

Cognizant Technical Interview Questions

Process for Grade A vs Grade B/C college

Cognizant has different interview process for Grad A colleges like VIT, Manipal, PESIT etc and different process for Grade B/C colleges which are not in the top 30 colleges of India.

  • Grade A colleges
    • Written Round + HR Interview ~ Results
  • Grade B college
    • Written Round + Technical and Coding Interview + HR Interview ~ Results

If applying for off Campus drive then doesn’t matter which Grade college yours is, Technical Interview Round will be there.

Process for CS-IT v/s non CS-IT

For CS-IT Students questions will be asked from following topics –

  • C Theory/Programs
  • C++ or Java
  • OOPS
  • Software Engineering
  • Final year Project
  • Optional – DBMS, Operating Systems, Data Structures

HR gives strict instructions to interviewers to stick to the above topics.

Optional – The interviewer will ask you if you know about these topics and only then he will ask you questions from this. A general way of asking is –

What is your favourite subject or Which subject did you recently study. Now, if only you say any of these topics then only interviewer will ask questions form those.

For non CS-IT students questions will be asked from following

  • Basic C Theory/Programs
  • C++ or Java
  • OOPS
  • Final Year Project
  • Optional Topic

Optional – The interviewer(who may not be from same branch as yours) will ask you. Your favourite topic or recently revised subject and will ask questions from that subject.

CTS Vs other Mass hiring Companies Interview Process Comparison

  1. Technical
    • CTS Interviewer will try to keep the Technical Round to basic C programming Codes(Find on CTS Coding Interview Dashboard), Basic theory and definitions and Focus more on your English.
    • Other companies like TCS and Tech Mahindra will not focus more on English speaking but your technical skills
  2. Duration of Interview
    • While in Accenture and CTS the duration of Interview is around 15 – 20 mins
    • For TCS it ranges anywhere between 30 mins to 45 mins, for Tech Mahindra it may be an hour or more.
  3. Coding Questions
    • Companies like Accenture and Deloitte don’t ask coding questions at all
    • But, Cognizant, TCS, Wipro will ask you coding questions like Palindrome, pattern printing etc even if you’re from Non CS IT round.
  4. C / OOPS Questions
    • Cognizant will necessarily ask some basic C / OOPS concept to all Branches. Well, you’re applying to an IT company they expect you to know a little about C / OOPS theory.
    • Companies like Accenture, Deloitte don’t ask C / OOPS concept. But, their training is very difficult, so even if you get selected. You need to learn all about coding and technical aspects
  5. Freedom of Topic Selection
    • All bulk companies, including Cognizant, give freedom of topic selection to you, generally the interviewer will ask you the favorite subject and will ask questions from that, or will ask you the questions from topics, chapters and projects mentioned in your Resume.

The following are trends in CTS Interview –

  1. They always keep chocolates in the room and offer them to students
  2. Always ask student
    • How was your day
    • Tell me about yourself(even in technical round)
  3. Try to make student comfortable if he/she is nervous
  4. Ask about bad scores in graduations, 10th or 12th

CTS asks interviewer to fill the interview feedback in 5 categories

  1. Strongly disagree
  2. Disagree
  3. Average
  4. Agree
  5. Strongly Agree

They will check mark one option from above for the following questions –


  1. Candidate has positive attitude towards learning
  2. Candidate is good at coding abilities
  3. Candidate has high potential to pick up a technology and expertise it, given he is provided with training
  4. Candidate has good proficiency in his core branch subjects
  5. Candidate is able to make cross arguments in professional English
  • What is a pointer?
  • What is a dangling pointer?
  • What is a data type?
  • What is size of integer data type?
  • What is the size of char data type?
  • What is the size of unsigned char?
  • What is the size of signed char?
  • What is the size of long?
  • What is the size of short?
  • What is the range of integer data type in C?
  • What is the size of float data type?
  • What is malloc?
  • What is the difference between do while and for loop?
  • What is a string?
  • /0 in string?
  • What is recursion?
  • What is printf?
  • What is math.h?
  • What is the argument of a function?
  • What is assignment operator in C?
  • What is the relational operator in C?
  • What is the logical operator in C?
  • What is the bitwise operator in C?
  • What are all decision control statements in C?
  • What are all loop control statements in C?
  • What is the difference between while and do-while loops in C?
  • What is the difference between single equal “=” and double equal “==” operators in C?
  • What is the difference between pre increment operator and post increment operator?
  • What is the difference between pre decrement operator and post decrement operator?
  • What is “&” and “*” operators in C?

If student says he knows Java

  1. Difference between C++ and Java?


  1. What are virtual Functions?
  2. What is overloading?
  3. What is overriding?
  4. What is polymorphism?
  5. What is data abstraction?
  6. What is encapsulation?
  7. What is inheritance?
  8. What is constructor?
  9. What is destructor?
  10. Abstract Classes vs Interfaces
  11. How to implement Multiple Inheritance in C++?
  12. What are the Features of OOPS?
  13. How to use this keyword?
  14. What is static keyword?
  15. What is a class?
  16. What is difference between struct and object?
  17. What is an object?
  18. What is friend function?
  19. What are access modifiers?
  20. Difference between private and protected?
  21. What is keyword Auto for?
  1. What is a Data Structure?
  2. What is Linked lists?
  3. Is array of data structure?
  4. Define a binary search Tree?
  5. What is a binary Tree?
    • A binary tree is one type of data structure that has two nodes, a left node, and a right node. In programming, binary trees are an extension of the linked list structures.
  6. What is difference between Push and Pop?
    • Pushing and popping applies to the way data is stored and retrieved in a stack. A push denotes data being added to it, meaning data is being “pushed” into the stack. On the other hand, a pop denotes data retrieval, and in particular, refers to the topmost data being accessed.
  7. What is the difference between a stack and array?
    • Stack follows a LIFO pattern. It means that data access follows a sequence wherein the last data to be stored when the first one to be extracted. Arrays, on the other hand, does not follow a particular order and instead can be accessed by referring to the indexed element within the array.
  8. What is a doubly linked Lists?
    • Doubly linked lists are a special type of linked list wherein traversal across the data elements can be done in both directions. This is made possible by having two links in every node, one that links to the next node and another one that connects to the previous node.
  9. What is a queue?
  10. What is a stack data structure?
  11. What is a graph?
  12. What is a priority queue?
  13. What is the time complexity of  linked list insertion?

Generally the interviewer may or may not be from your branch so he will ask questions from Google about your branch.

Mostly, the interviewer tries to stick to C/OOPS or coding questions but some interviewers depending on their personal choice may ask you your branch specific questions –

  1. How shear forces are incurred in fluid flow ?
    • Shear forces between fluid particles and boundary walls and between the fluid particles themselves, result from the viscosity of the real fluid.
  2. In laminar flow, how discharge is related to viscosity?
    • Discharge varies inversely as viscosity.
  3. What is best hydraulic section?
    • Best hydraulic section is one in which for a given cross-section area, the channel section has least wetted perimeter.
  4. What is best hydraulic trapezoidal section?
    • It is a half-hexagon in shape.
  5. What is specific energy in a channel section?
    • It is defined as the energy head measured with respect to the channel bottom at the section. At any section, it is equal to sum of the velocity head and the water depth at the section.
  6. What is critical depth and critical flow?
    • Critical depth is the depth, at which the discharge may be delivered through the section at minimum energy. Critical flow is the flow in open channel corresponding to critical depth.
  7. What causes boundary layer separation?
    • An adverse pressure gradient.
  8. What is the importance of Nose radius?
    • Nose radius is favorable to long tool life and good surface finish. A sharp point on the end of a tool is highly stressed, short lived and leaves a groove in the path of cut.
  9. At what point below free surface in a uniform laminar flow in a channel the point velocity is equal to mean velocity of flow?
    • At 0.577 depth of channel.
  10. What is the value of friction factor for smooth pile when Reynolds number is approximately = 10G?
    • 0.01.
  11. How hydraulic grade line and free surface of open channel flow related?
    • They coincide.
  12. What are the first and last elements of tool signatures?
    • Back rake angle and nose radius.
  13. What is open channel flow ? Explain 4 types of open channel flows.
    • Open channel flow has a free water surface which is normally subject to the atmospheric pressure.
    • Steady open channel flow : In this case the discharge and water depth at any section in the reach do not change with time during the period of interest.
    • Unsteady open channel flow : In this case the discharge and the water depth at any section in the reach change with time.
    • Uniform open channel flow : In this case the discharge and the water depth remain the same in energy section in the channel reach. It is mostly steady.
    • Varied open channel flow : In this case the water depth and/or the discharge change along the length of the channel. It may be steady (such as flow over a spillway crest) or unsteady (as in the case of flood waves or tidal surge).
  14. When does wake occur?
    • It occurs after a separation point.
  15. In straight polarity, to which terminal the electrode is connected?
    • Negative.
  16. What is hydraulic radius?
    • It is the ratio of fluid flow area/shear perimeter.
  17. Define flow work.
    • Flow work is the amount of mechanical energy required to push or force a flowing fluid across a section boundary.
  18. What do you understand by dimensional analysis ?
    • Dimensional analysis is the mathematics of dimensions and quantities and provides procedural techniques whereby the variables that are assumed to be significant in a problem can be formed into dimensionless parameters, the number of parameters being less than the number of variables.
  19. What is hydraulic depth for open channel flow ?
    • It is the ratio of area and the top width of the channel section.
  20. Which welding set will you select for welding both ferrous and non ferrous materials?
    • D.C. generator set.
  21. Which welding process is a combination of arc welding and gas welding processes?
    • Atomic hydrogen welding.
  22. What is hydraulic jump ?
    • It is a natural phenomenon in open channel. It is an abrupt reduction in flow velocity by means of a sudden increase of water depth in the down stream direction. Through a hydraulic jump, and high-velocity supercritical flow is changed to a low-velocity subcritical flow.
  23. What is gradually varied flow ?
    • The changes in water depth in the open channel take place very gradually with distance. Depending on the channel slope, the surface conditions, the sectional geometry, and the discharge, these may be classified into five categories : steep channel, critical channel, mild channel, horizontal channel, and adverse channel.
  24. Explain 3 types of channels.
    • Steep channel : In this case normal depth < critical depth. Critical channel : In this case normal depth = critical depth. Mild channel : In this case, normal depth > critical depth.
    • Adverse channel : In this case, the slope of channel bed < 0.
    • Horizontal channel : In this case, the slope of channel bed = 0.
  25. Mention two major differences between shaper and planer ?
    • Shaper / Planer
      •  The cutting tool reciprocates (a) Work reciprocates
      • The work is stationary (b) Tool is stationary
      • Meant for small work pieces (c) Meant for large work pieces.
      • Only lighter cut can be taken (d) Heavy cuts can be taken.
      • Tools are smaller in size (e) Tools are bigger in size.
  26. Differentiate between drilling and reaming?
    • Drilling / Reaming
      • It is the operation of initiating hole (a) Reaming is the operation of finishing and sizing a drilled/bored hole.
      • It can be done at relatively high speeds (b) It should be done only at slow speeds.
      • Larger chips are produced (c) Less chips are produced.
      • Drill has only two flutes (d) Reamer has more than 4 flutes.
      • Drill has chisel edge (e) Reamer has a bevel edge.
  27. What is similarity between normal shock wave and hydraulic jump ?
    • Both are analogous and irreversible.
  28. For what purpose chills are used in moulds ?
    • Chills are used to achieve directional solidification.
  29. What is tumbler gear mechanism ?
    • Tumbler gear mechanism is a mechanism consisting of number of different sized gears keyed to the driving shaft in the form of cone and is used to give the desired direction of motion of the lathe spindle.
  30. What is relative roughness of pipe ?
    • It is the ratio of the size of the surface imperfections to the inside diameter of the pipe.
  31. What is conicity ?
    • The ratio of the difference in diameter of the taper to its length is termed conicity.
  32. Under what condition the effect of compressibility of fluid can be neglected?
    • When Mach number is less than 0.4.
  33. For which type of flow the velocity distribution in a pipe is parabolic.
    • For uniform laminar flow.
  34. What is the relationship between center line velocity and average velocity for a laminar flow in a pipe ?
    • Average velocity = 1/2 centre line velocity.
  35. On which factor the friction factor for a smooth pipe in turbulent flow depends ?
    • Reynolds number.
  36. What do you understand by pipe branchings ?
    • When water is brought by pipes to a junction where more than two pipes meet, them the total amount of water brought by pipes to a junction must always be equal to that carried away from the junction by other pipes, and all pipes that meet at the junction must share the same pressure at the junction.
  37. What is pipe networks and what are the condition for network ?
    • Pipe network comprises a number of pipes connected together to form loops and branches. For a network,
      • at any junction, Y.Q = 0 and between any two junctions the total head loss is independent of the path taken.
  38. What is Hardy-Cross Method ?
    • It is a commonly used computer program for a pipe network.
  39. Explain water hammer.?
    • The force resulting from changing the speed of the water mass (say in a pipe due to sudden change of flow rate) may cause a pressure rise in the pipe with a magnitude several times greater than the normal static pressure in the pipe. Pressure head caused by water hammer = C (V – velocity in pipe, C = celerity).
  40. What happens to impurities in centrifugal casting ?
    • They get collected at the center of the casting.
  41. Define the terms hydraulic similitude and dimensional analysis.
    • Hydraulic similitude is the principle on which the model studies are based.
    • Dimensional analysis is the analysis of the basic relationship of the various physical quantities involved in the static and dynamic behaviors of water flow in a hydraulic structure.
  42. Explain the difference between geometric similarity, kinematic similarity and dynamic similarity.
    • Geometric similarity : It implies similarity of form. The model is a geometric reduction of the prototype and is accomplished by maintaining a fixed ratio for all homologous lengths between the model and the prototype.
    • Kinematic similarity : It implies similarity in motion. Kinematic similarity between a model and the prototype is attained if the homologous moving particles have the same velocity ratio along geometrically similar paths. It involves the scale of time as well as length.
    • Dynamic similarity : It implies similarity in forces involved in motion.
  43. Define Reynolds law ?
    • When the inertial force and the viscous force are considered to be the only forces governing the motion of the water, the Reynolds number of the model and the prototype must be kept at the same value.
  44. When a built up edge is formed while machining ?
    • While machining ductile materials at high speed.
  45. On what factor the friction factor for a rough pipe in turbulent flow depends ?
    • Relative roughness.
  46. What is unit power of a turbine ?
    • PHP12.
  47. How cavitation causes damage ?
    • In a a closed system (pipelines, or pumps), water vaporises rapidly in regions where the pressure drops below the vapour pressure. This phenomenon is called cavitation. The vapour bubbles formed in cavitation usually collapse in a violent manner, which may cause considerable damage to the system.
  48. In milling process, how the arbor torque can be smoothend ?
    • Arbor torque can be smoothened by increasing number of teeth, using higher spiral angle of teeth, using higher cutting depth.
  49. What are webs in a twist drill ?
    • Webs are the metal column in the drill which separates the flutes.
  50. What is bluff body ?
    • It is a body with such shape that the flow is separated much ahead of its rear end resulting in a large wake, the pressure drag being much greater than the friction drag.
  51. What is bulk modulus ?
    • It is the ratio of hydrostatic stress to volumetric strain within the elastic limits.
  52. Define boundary layer.
    • It is the fluid layer in the neighborhood of a solid boundary where the effects of fluid friction are predominant.
  53. What is creep flow ?
    • It is flow at very low Reynolds number where viscous forces are larger than the inertia forces.
  54. What is Torricellis theorem ?
    • According to it velocity of jet flowing out of a small opening is proportional to the square root of head of liquid above it.
  55. How does cavitation manifest itself in a centrifugal pump ?
    • Usual symptoms of cavitation of pump are noise, vibration, a drop in head and capacity with a decrease in efficiency, accompanied by pitting and corrosion of the impeller vanes.
  56. What happens if centrifugal pump is operated at excessive speeds?
    • When a pump is operated at excessive speeds, the differential pressure developed increases and causes a powerful pulsating vacuum on the underside of the blade tips and each particle of water is pulled away from the blade, taking away with it a small particle of metal, producing pitting/grooved effect. Repeated erosive action results in complete honey combing and total destruction of blade, with resultant loss in pump performance.
  57. On what parameters the head developed by a centrifugal pump depends ?
    • It depends upon the impeller diameter and its rotative speed.
  58. Which factors determine the selection of electrolyte for electrochemical machining process ?
    • Electrolyte should be chemically stable and have high electrical conductivity.
  59. What is the disadvantages of centrifugal pump having very low specific speed ?
    • For a centrifugal pump having very low specific speed, the impeller diameter is large and narrow having excessively high disc friction and excessive hydraulic losses.
  60. On what factors the efficiency of pump depends ?
    • Efficiency of a pump (centrifugal) depends on the size, speed, and proportions of the impeller and casing.
  61. On what factors the cavitation in centrifugal pumps is dependent ?
    • Cavitation in centrifugal pumps depends on the velocity of water entering the impeller and on the relative velocity of the impeller blades where the water is picked up.
  62. What are the losses in a centrifugal pump ?
    • The losses in a centrifugal pump are : Friction losses due to eddies in flow, leakage, friction loss due to rotation of impeller in chamber of water, gland and bearing power losses.
  63. What should be done to avoid cavitation in pumps ?
    • In order to avoid cavitation, the suction lift and the operating speed must be carefully chosen.
  64. What will happen if speed of reciprocating pump is increased ?
    • If speed of a reciprocating pump is increased beyond a limit, then atmospheric pressure would be insufficient to force water into the pump at the same speed as the piston. This would a break in the continuity of the water in suction pipe (cavitation) and give rise to vibration, noise, and chemical attack by any dissolved gases which may be released from the water owing to the high vacuum and the breaking of the water column.
  65. What is the order of efficiency of centrifugal and reciprocating pumps ?
    • The efficiency of centrifugal pump is of the order of 45% whereas that of reciprocating pump is around %.
  66. What are the basic operations performed in a slotter ?
    • The different operations done in slotter are :
      • Machining grooves
      • Machining cylindrical surface
      • Machining irregular profiles.
  67. How the positive displacement is obtained in rotary pumps ?
    • Positive displacement in rotary pumps is achieved in two ways :
      • A rotor carries radially adjustable vanes, the outer tips of which are constrained by a circular casing, whose centre is remote from that of the rotor.
      • Various combinations of gears, lobes, helices, etc. within a casing arranged so that the lobes or teeth attached to each rotor pass in sequence through the same pumping space.
  68. How a slotter differs from shaper ?
    • Slotter / Shaper
      • Ram reciprocates vertically / Ram reciprocates horizontally
      • It has a circular table / It has a rectangular table
      • Suited for machining internal surfaces / Suited for machining external surfaces
      • Table can take less load / Table can take much load
  69. Under what condition the flow and power of pump vary as square of the size ?
    • The flow and power vary as size2 when the geometric size changes as inverse of change of speed.
  70. How the incidence of cavitation detected ?
    • The incidence of cavitation is detected by the following in order of appearance.
      • stroboscopic observation of bubble appearance and size
      • sensitive acoustic tests of cavitation noise
      • reduction of efficiency and/or head of 3%.
  71. How cavitation erosion is assessed ?
    • Cavitation erosion is assessed by depth of attack or weight of metal removed.
  72. At which temperature the cavitation erosion is negligible and why ?
    • Cavitation erosion is negligible at above 300°C because the water and steam have same densities at critical temperature of 374°C and thus there is no volume change or bubble collapse in the vicinity of this range.
  73. What is an arbor?
    • An arbor is an accurately machined shaft for holding and driving the arbor type cutter. It is tapered at one end to fit the spindle nose and has two slots to fit the nose keys for locating and driving it.
  74. For a body to float in stable equilibrium where the e.g. should be located w.r.t. metacentre ?
    • e.g. should be below metacentre.
  75. What is the condition for a flow to be fully developed through a pipe ?
    • Ratio of maximum velocity to average velocity should be 2.
  76. When a fluid is moving with uniform velocity, whether the pressure of fluid will depend on its depth and orientation ?
    • No.
  77. How much is the vertical component of force on a curved surface submerged in a static liquid ?
    • It is equal to weight of the liquid above the curved surface.
  78. On which factors depends the friction factor in a rough turbulent flow in a pipe ?
    • It depends on pipe diameter and the condition of the pipe.
  79. What does the realisation of velocity potential in fluid flow indicate ?
    • It indicates that flow is irrotational.
  80. What is the difference between potential flow and creep flow ?
    • Potential flow assumes viscous forces to be zero but same is considered larger than inertia forces in creep flow.
  81. For which application Mach number and Froude numbers are significant ?
    • Mach no. is significant in the study of projectiles and jet propulsion. Froude number is significant in the study of ship hulls.
  82. What is the difference between geometric, kinematic, and dynamic similarities between model and prototype ?
    • Geometric similarity is mainly for same shape for model and prototype, kinematic similarity is concerned with stream line pattern, whereas dynamic similarity concerns the ratio of forces.
  83. A body is floating in water. If it is displaced slightly then about which point it will oscillate.
    • It will oscillate about centre of buoyancy.
  84. Why uniform ramming is considered desirable in green sand moulding process ?
    • Uniform ramming results in greater dimensional stability of a casting.
  85. On what account the friction drag is experienced ?
    • Friction drag is experienced on separation of boundary layer.
  86. What is the characteristic of centrifugally cast components ?
    • These have fine grain structure with high density.
  87. Under what condition the separation of flow occurs ?
    • When pressure gradient changes abruptly.
  88. What is the criterion for shaping of streamlined body ?
    • It is shaped to suppress the flow separation about the body and to shift the boundary layer separation to near most part of body to reduce the wake size.
  89. What do you understand by entrance length and what is its value for turbulent flow in smooth pipe ?
    • Entrance length of flow is the initial length in which the flow develops fully such that the velocity profile remains unchanged downstream. For turbulent flow in smooth pipe, entrance length is taken as 50 x diameter of pipe.
  90. Explain the difference between friction drag and pressure drag.?
    • Friction drag is the drag force exerted by a fluid on the surface due to friction action when the flow occurs past a flat surface at zero incidence. Pressure drag is the additional drag force on account of the differences of pressure over the body surface when flow occurs past a surface which is not everywhere parallel to the fluid stream. Pressure drag depends upon separation of boundary layer and the size of wake. Friction drag is due to shear stresses generated due to viscous action.
  91. What do you understand by choking in pipe line ?
    • When specified mass flow is not able to take place in a pipe line.
  92. What is the difference between streamline body and bluff body ?
    • In streamline body the shape is such that separation in flow occurs past the nearmost part of the body so that wake formed is small and thus friction drag is much greater than pressure drag. In bluff body the flow gets separated much ahead of its rear resulting in large wake and thus pressure drag is much greater than the friction drag.
  93. What is the difference between dressing and trueing of a grinding wheel ?
    • Dressing is the process used to clear the cutting surface of the grinding wheel of any dull grits and embedded swarf in order to improve the cutting action. Trueing is the process employed to bring the wheel to the required geometric shop and also to restore the cutting action of a worn wheel.
  94. Whether hard grade or softer grade is required for internal grinding than external grinding?
    • Softer graders of wheel are required for internal grinding than for external grinding.
  95. How is the velocity profile and stress distribution due to laminar flow of an incompressible flow under steady conditions in a circular pipe.
    • Velocity profile is parabolic with zero velocity at boundary and maximum at the centre. Shear stress distribution is linear, being maximum at boundary and zero at centre.
  96. Where the maximum velocity occurs in open channels?
    • Near the channel bottom.
  97. Define hydraulically efficient channel cross section.
    • The shape of such section is that which produces minimum wetted perimeter for a given area of flow and carries maximum flow.
  98. What is follower rest ?
    • For slender work a travelling or follower rest is used. This fits on the lathe – saddle and travels to and for with it. By this means support is constantly provided at the position of cut. Thus the work piece being turn is rigidly held against the tool.
  99. What is the meaning of the term sensitive drill press ?
    • A sensitive drilling press is a light, simple, bench type machine for light duty working with infinite speed ratio.
  100. Why carburised machine components have high endurance limit ?
    • In carburised machine components, the process of carburisation introduces a compressive layer on the surface and thus endurance limit is increased.

Very basic questions are asked regarding you project. Some of them are:

  • What was the duration of the project?
  • On what technologies or, what is the domain of the project?
  • Was it a team project or an individual project?
    • If it was a team project:
      • What was your role in the team?
      • What were the difficulties that you faced?
      • What did you learn by working in a group or, what are your views on team-work?
    • If it was an individual project:
      • Were you able to manage the load of the project all by yourself?
      • What kind of difficulties did you face?
  • If it was an internship based project, what was the name of the company?
  • Do you have any questions for us?
  • Would you like some chocolates?
  • Send the next student inside the room.
  1. Define software engineering.
    • Software engineering is made up of two terms that is software and engineering.

      • Software refers to the set of instructions that tells a computer what to do and how to perform any tasks.
      • Engineering is the work to build and design something in an effective manner.

      Software engineering is an engineering branch to develop a software product using some scientific principles and procedures. The result will be an reliable and good quality product.

  2. What are the various types of software maintenance?
    • There are basically 4 types of software maintenance. They are :
      1. Corrective Maintenance: To correct any type of error present in the software product, the corrective maintenance is used.
      2. Adaptive Maintenance: As new technology emerges, the software is updated by taking up the adaptive maintenance.
      3. Perfective Maintenance: The object of perfective maintenance is to improve software reliability and performance and adding some new things in software product.
      4. Preventive Maintenance: There is need of updation to prevention or correction of future errors of the software.
  3. Define software testing?
    • Software Testing is the process to ensure that the software product is error free or not ? Testing process is used to identify that the software product fulfills the requirements of the customer. In another words, testing is defined as the execution of the software product to find the errors present in the system. This process is done for checking that the software product works according to the design and implementation of the software or not?
  4. What is white box testing ?
    • White box testing is also called Clear Box Testing, Open Box Testing, Glass Box Testing, Transparent Box Testing, Code-Based Testing and Structural Testing.
    • White box testing is a software testing in which the internal structure of the program is tested. The tester knows the interior functionality and design of the code and internal paths. This testing is usually done by developers.
    • White-box is a term which is used because of see-through box concept. The white box means that the tester can see internal working through the box. Hence this method is named white box testing. 
  5. What are the Advantages and Disadvantages of white box testing?
    • Advantages:
      1. Entire code and structures are tested in the white box testing.
      2. It results in the optimization of code removing error and helps in removing extra lines of code.
      3. This testing can start at an earlier stage.
      4. White box testing is easy to automate.
    • Disadvantages:
      1. This testing is very expensive and time-consuming.
      2. Redesign of code needs test cases to be written again.
      3. Missing functionalities cannot be detected.
      4. This technique can be very complex and at times, not realistic.
  6. What is Black box testing?
    • Black box testing is also called as “Behavioral Testing, opaque-box, closed-box, specification-based or eye-to-eye testing”.
    • In the black box testing, testers only tests the functionality or working of the software product. Testers don’t know about the interior structure of the code and internal path of the system.
    • Testers only select a function and give the inputs and check outputs corresponding to the inputs  of the system.
    • Tester gives valid and invalid inputs & determines the correct expected results. All the test cases are designed based on the  requirements & specifications document.
  7. What is Unit testing?
    • Unit testing is a level of software testing in which individual units/components are tested. 
    • A unit is a smallest testable part/module of any software application. In procedural programming, a unit is an individual program, function, procedure. In object-oriented programming, a unit may be a method.
    • Unit testing of the software product is done during the software development stage saves time and money in the end. 
  8. What is meant by Smoke testing?
    • Smoke testing is also known as “Confidence Testing” or ”Build Verification Testing”.
    • This testing is done after developing the software product. Smoke testing is done on the particular build.
    • In this testing, software build is evaluated hence the name is “build verification testing”.
    • Smoke testing is inspired from the hardware testing in which device passed the test if it did not catch smoke once it was turned on.
  9. What is Alpha testing and Beta testing?
    • Alpha Testing:
      1. Alpha Testing is a type of acceptance testing which is used to find the defects/bugs in the software application before delivering the product to the customers or public. 
      2. This testing is used to determine the readiness for beta testing.
      3. Alpha testing is performed at the end of software development and before Beta Testing.
      4. This testing is performed at the developer’s site – testing environment by the internal teams.
      5. In this testing, only the functionality and usability of the application is evaluated.
    • Beta Testing:
      1. In the development of the software, this is a second and last phase of testing.
      2. This testing is performed after the alpha testing but before the delivering of the product to the customers or market.
      3. Beta testing is also known as “Field Testing” or “Pre-release Testing”.
      4. This testing is performed at the client site or the end users or stakeholder of the product. 
      5. Beta testing is a type of acceptance testing which focuses on the quality of the software product.
  10. What is SDLC ?
    • SDLC stands for Software Development Life Cycle. There are various software development models which is used in software development life cycle to represent the process of building a software. SDLC models defines all the phases of software development.

      SDLC models can have a different methodology but the phases remains the same. The development team chooses the best SDLC model to develop a software product so that the efficient and reliable software product is developed. By using SDLC models, you can develop a software product in a systematic and nice way.

      Here are some important SDLC models given below-

      • Waterfall Model
      • Iterative Waterfall Model
      • Agile Model
      • Spiral Model
      • Prototype Model
      • V model
      • RAD model
  11. What is Waterfall model?
    • Waterfall Model – This is the first software development model. Waterfall model is the linear sequential model in which all the phases works in a sequential manner. The output of the previous phase is the input for the upcoming phase. But we cannot go back to the prior stage to change requirements. There is no overlapping between the phases of the software development. This model takes less time to develop and very easy to understand.
    • Cognizant technical Interview most asked questions
      It is easy to use and understand.

      This model does not work well for large projects.

      No overlapping between the phases.We cannot go back at previous phase to change anything or any requirement.
      This model is suitable for small projects.

      No changes can be made in the project.

      It is a linear sequence model. It works in a flow step by step.It can take a long time to complete the project.
      High visibility because output of each phase is generated for the next phase.

      If customer does not satisfied with the project then it is hard to change the requirements.

      It provides more flexibility and is easy to maintain.

      High risk to make a project.

  12. What is spiral model in SDLC?
    • Spiral model – The spiral model is the integration of waterfall model and iterative model. This model contains four phases that is planning, risk analysis, development & testing and evaluation. After completing each iteration, customer evaluates the software product and give feedback. On the basis of customer feedback, developers starts the next iteration of the software development.
    • Spiral SDLC

      This model is good for large and complex projects.

      Spiral model is not good for small projects.

      Updates are received to the customer at each iteration.

      This model is more complex and difficult to understand if a new employee is entered in the project development.

      Spiral model is suitable to change the requirements at any time, any phase.

      Not defined end points of the project , so it can take a long time to develop or iterations can be go infinitely.

      Documentation is clearly defined and understandable.

      Fast development and software is built at the SDLC .

  1. What is an Operating System?
    • The connecting interface between the hardware of the computer and the end user or his actions is called operating system. Operating system carries out tasks asked to implement by end user, or supporting tasks to provide functionality to end user with the help of computation power and support provided by hardware of the system.

  2. What is an process?
    • process can be defined as a program in execution or instance of a program of the system. A process is basically a running or an active entity as compared to a program which is a static term.

  3. What are the 5 states in a process life cycle?
    • A process can be in any of the following 5 states:  New State, Ready State, Running State, Waiting State and Terminated State.

  4. What is process scheduling in an Operating System ?
    • The decision to move different parallel processes competing with one another for execution, to different states like Ready to running or running to exit state based on a certain decision strategy. Handled by – Process Manager

  5. What are the different types of process scheduling in an Operating System ?
    • We divide Process Scheduling into following two types: 

      • Preemptive Scheduling –The scheduling in which a running process can be interrupted if a high priority process enters the queue and is allocated to the CPU is called preemptive scheduling. In this case, the current process switches from the running queue to ready queue and the high priority process utilizes the CPU cycle.
      • Non Preemptive Scheduling – The scheduling in which a running process cannot be interrupted by any other process is called non-preemptive scheduling. Any other process which enters the queue has to wait until the current process finishes its CPU cycle. 
  6. What is a job queue, ready queue and a device queue ?
    • There are the following types of queues –

      1. Job Queue – Whenever any process enters the system its there in job Queue
      2. Ready Queue – Processes in the ready queue waiting for run time are in the ready queue.
      3. Device Queue – Some processes may be waiting some I/O operation, such processes are in the device queue.
  7. What are the different types of schedulers ?
    • There are three type of schedulers categorically –

      1. Long-term Scheduler: Also knowns as Job Scheduler. It selects the process that are to be placed in ready queue. The long term scheduler basically decides the priority in which processes must be placed in main memory. Processes of long term scheduler are placed in the ready state because in this state the process is ready to execute waiting for calls of execution from CPU which takes time that’s why this is known as long term scheduler.
      2. Short-term Scheduler: It decides the priority in which processes is in the ready queue are allocated the central processing unit (CPU) time for their execution. The short term scheduler is also referred as central processing unit (CPU) scheduler.
      3. Medium-term Scheduler: Also knowns as CPU Scheduler. It places the blocked and suspended processes in the secondary memory of a computer system. The task of moving from main memory to secondary memory is called swapping out. The task of moving back a swapped out process from secondary memory to main memory is known as swapping in. The swapping of processes is performed to ensure the best utilization of main memory.
  8. What is context switching ?
    • Context Switching is a cost and time saving measure performed by the CPU that is handing task 1 and has to stop executing this task to priority execute another task 2. To do this effectively, the system stores the initial task in its processed form so that when this task is resumed, it can be loaded and resumed from the same progress point as earlier.

      This allows the computer to multitask and multiple processes can share the same CPU. This is also done to make sure that tasks do conflict one another, as they may be holding a same resource for execution like memory etc.

  9. What is process synchronization?
    • When several threads (or processes) share data, running in parallel on different cores , then changes made by one process may override changes made by another process running parallel, resulting in inconsistent data. So, this requires processes to be synchronized, handling system resources and processes to avoid such situation is known as Process Synchronization.

  10. What do you mean by Inter Process Communication?
    • Inter Process Communication (IPC) is the mechanism by which cooperating process share data and information. There are 2 ways by which Inter process communication is achieved –

        • Shared Memory
        • Message Parsing
  11. What is a semaphore ?
    • Semaphore is also an entity devised by Edsger W. Dijkstra, to solve Process Synchronization problem in OS. Its most popular use is it solve Critical Section algorithm. It uses signaling mechanism to allow access to shared resource namely by two – (A) Wait and (B) Signal.

  12. What do you mean by a Deadlock ?
    • Deadlock refers to the condition when 2 or more processes are waiting for each other to release a resource indefinitely. A process in nature requests a resource first and uses it and finally releases it. But in deadlock situation, both the processes wait for the other process.

  13. What are deadlock prevention techniques ?
    • The way to prevent deadlock is to ensure that at least one of these conditions do not hold :

      • Mutual exclusion – If 1 resource is non- shareable , then mutual exclusion condition must hold. We can’t prevent deadlock by denying this mutual exclusion condition, as some resource are inherently non shareable and this can’t be changed.
      • Hold And wait – For Hold and wait condition to never occur, it should be made sure that whenever a process requests a resource, it does not hold any other resource. There can be many protocols implemented –
        • One protocol could be allocating all resources to a process before its execution .
        • Other Could be , A process can request resource only when it has no resource.
  1. What do you mean by a Database ?
    • Database is a collection of related data, which is organized in a structured and a meaningful way.
  2. What is DBMS ?
    • DBMS stands for Database Management System. It is a software that controls all the different manipulations of stored or, to be stored data in a database. It allows, creation, updation, manipulation, definition of a database.
  3. What is RDBMS ?
    • RDBMS stands for Relational Database Management system. It is a software system or collection of various programs that work together on a relational data model database and offer various integrated entities like – Database administration, Data definition, creation, updation etc. Some examples of RDBMS are –
      • SQL
      • mySQL
      • IBM DB2
      • Oracle
      • Microsoft Access

      RDBMS was introduced by E. F. Codd.

  4. What is SQL ?
    • SQL stands for Structured Query Language. It is a language that is designed specifically for performing interactions  with relational databases. SQL is an ANSI (American National Standards Institute) standard.
  5. What are the different types of SQL commands?
    • This is one of the most frequently asked SQL Interview Questions for freshers. SQL commands are broadly classified into 4 categories. They are –
      1. DDL (Data Definition Language) : DDL is used to define the structure of the database or the schema.  CREATE, ALTER, DROP and TRUNCATE table are a few of the DDL commands used.
      2. DML (Data Manipulation Language): DML is used for manipulation of the data. In other words, DML statements are used for data management. Examples include are INSERT, DELETE, UPDATE. 
      3. DQL (Data Query Language): DML statements are used to perform queries on the existing Database. Ex: SELECT statement.
      4. DCL (Data Control Language): DCL is used to control the access to data which is stored in the Database. Example – GRANT and REVOKE. They provide access permissions to different kinds of users to access data in the database based on privileges(Like admin or a normal user or a super user).
  6. What is a Record in a database?
    • Generally, the database table is  viewed  as a collection of records. The term record is often also called tuple and row in a database table. Each record represents a complete information of the specific data item, each record stores different data with the same structure.
  7. What is a Table in a database?
    • A table is a collection of records of a particular type. For example, employee table, student table etc.
  8. What is a database transaction?
    • A transaction is basically a set of logical instructions that is either executed entirely or it doesn’t get executed at all. Database transaction takes a database from one consistent state to another.
  9. What are properties of a transaction?
    • Following are the properties of a transaction (ACID Properties).
      1. Atomicity – A transaction has many sequence of steps. When all the instructions in a transaction get executed, it will get reflected in the database, if by chance any instruction does not get executed, the entire transactions is rolled back. In other words, a transaction should either take place entirely, or does not occur at all.
      2. Consistency – In a transaction, database moves from one state to another. This property says that the consistency or the correctness of the database should be maintained before and after the transaction. 
      3. Isolation – Every transaction should be executed as if it is the only transaction to be executed in the system. This implies that many transactions can take place concurrently without interfering with one another which may lead to inconsistency in the database. 
      4. Durability – Once a transaction has been successfully executed, the updates must be saved  for all other transactions on a permanent storage device such as a disk.
  10. What are the different type of normalization?
    • Normalization is a  step-by-step process via which we reduce the complexity of a database. The database may have a lot of redundancies (unnecessary information that has become outdated or no longer useful) like attendance record for former students in a university. Four major types of normalizations are 
      1. First Normal Form (1NF): A relation is said to be in 1NF if and only if it does not have any multivalued attributes. Example: A Student table containing a Phone number column must contain only one phone number (value). After 1NF, we can still have redundant data.
      2. Second Normal Form (2NF): A relation is said to be in 2NF if and only if it is in 1NF and NO Non Prime attribute should be dependent on any Candidate key element, which is called not having partial dependency. After 2NF, we can still have redundant data.
      3. Third Normal Form (3NF): A relation is said to be in 3NF, if and only if it is in 2NF and there should not be any transitive dependency for non prime attributes.
      4. Boyce-Codd Normal Form(BCNF): A relation is said to be in BCNF, if and only if it is in 3NF and every non-trivial function dependency A -> B is a super key. In simple words, LHS should always be a super key.
  11. What is a candidate key?
    • A candidate key is the smallest set of attributes that can uniquely identify a row in a table. Example: A table containing attributes such as PAN no., Aadhar card no., Name and State, the attributes PAN no. and Aadhar no. can be considered as candidate keys.
  12. What is a primary key?
    • Out of all the candidate keys, a primary key is chosen that can  uniquely identify every row in a table. Primary key values can never be reused and should always be unique. If a row is deleted from the table, its primary key may not be assigned to any new rows in the future.
  13. What is an Alternate Key?
    • When a primary key is chosen from the set of candidate keys, the remaining keys are known as Alternate Keys.
  14. What is a Composite Key?
    • A composite key is a combination of one or more attributes. If a single column alone fails to be served as a primary key then a combination of columns would help to uniquely access a record from the table. Such type of keys or nothing but composite keys.
  15. What is a Foreign Key?
    • The foreign key constraint is a column or a list of columns which points to the primary key column of another table.
  16. What is a Unique Key?
    • Unique key is same as primary key with the difference being the existence of null values. Unique key field allows one value as NULL value whereas a primary key does not allow NULL values.

2 comments on “Cognizant Technical Interview Questions”

    • Chirag

      see my technical interview in cognizant was very good. Interviewer asks questions related to oops,and then i was asked to sort my name and a program for polymorphism and some questions related to operators and my project.

      But in hr interview i was asked about the company, introduce yourself,are you willing to relocate but the main problem was last question in which hr interview asked me about artificial intelligence and there was some condition like i don’t have to take pause…if a minor pause is there then my interview will end at that point only….and frankly speaking after 6,7 seconds i have minor pause and then he directly told me that I’m done with you….my hr interview lasted for about 3 mintues that’s it….i found interviewer a bit rude……