Top 100 Codes

June 5, 2025

PrepInsta Top 100 Codes

Below You will find some of the most important codes in languages like C, C++ and Java. These codes are of prime importance for college semester exams and also for various online tests and interviews of the companies offering placements within varying range in LPA.

These codes are very important since these will help you clear your basic concepts in various languages.

Getting Started

Introduction to Top 100 codes
ASCII Table
Positive or Negative number: C | C++ | Java | Python
Even or Odd number: C | C++ | Java | Python
Sum of First N Natural numbers: C | C++ | Java | Python
Sum of N natural numbers: C | C++ | Java | Python
Sum of numbers in a given range: C | C++ | Java | Python
Greatest of two numbers: C | C++ | Java | Python
Greatest of the Three numbers: C | C++ | Java | Python
Leap year or not: C | C++ | Java | Python
Prime number: C | C++ | Java | Python
Prime number within a given range: C | C++ | Java | Python
Sum of digits of a number: C | C++ | Java | Python
Reverse of a number : C | C++ | Java | Python
Palindrome number: C | C++ | Java | Python
Armstrong number : C | C++ | Java | Python
Armstrong number in a given range : C | C++ | Java | Python
Fibonacci Series upto nth term : C | C++ | Java | Python
Find the Nth Term of the Fibonacci Series : C | C++ | Java | Python
Factorial of a number : C | C++ | Java | Python
Power of a number : C | C++ | Java | Python
Factor of a number : C | C++ | Java | Python
Finding Prime Factors of a number : C | C++ | Java | Python
Strong number : C | C++ | Java | Python
Perfect number : C | C++ | Java | Python
Perfect Square : C | C++ | Java | Python
Automorphic number : C | C++ | Java | Python
Harshad number : C | C++ | Java | Python
Abundant number : C| C++ | Java | Python
Friendly pair : C | C++ | Java | Python

Working with Numbers

Highest Common Factor(HCF): C | C++ | Java | Python
Lowest Common Multiple (LCM) : C | C++ | Java | Python
Greatest Common Divisor : C | C++ | Java | Python
Binary to Decimal to conversion : C | C++ | Java | Python
Octal to Decimal conversion : C | C++ | Java | Python
Hexadecimal to Decimal conversion: C | C++ | Java | Python
Decimal to Binary conversion: C | C++ | Java | Python
Decimal to Octal Conversion: C | C++ | Java | Python
Decimal to Hexadecimal Conversion: C | C++ | Java | Python
Binary to Octal conversion : C | C++ | Java | Python
Octal to Binary conversion : C | C++ | Java | Python
Quadrants in which a given coordinate lies : C | C++ | Java | Python
Permutations in which n people can occupy r seats in a classroom : C | C++ | Java | Python
Maximum number of handshakes: C | C++ | Java | Python
Addition of two fractions: C | C++ | Java | Python
Replace all 0’s with 1 in a given integer : C | C++ | Java | Python
Can a number be expressed as a sum of two prime numbers : C | C++ | Java | Python
Count possible decoding of a given digit sequence : C | C++ | Java | Python
Calculate the area of a circle : C | C++ | Java | Python
Find the prime numbers between 1 to 100 : C | C++ | Java | Python
Calculate the number of digits in an integer : C | C++ | Java | Python
Convert digit/number to words : C | C++ | Java | Python
Counting number of days in a given month of a year: C | C++ | Java | Python
Finding Number of times x digit occurs in a given input : C | C++ | Java | Python
Finding number of integers which has exactly x divisors: C | C++ | Java | Python
Finding Roots of a quadratic equation : C | C++ | Java | Python

Codes for Recursion

Power of a Number – C | C++ | Java | Python
Prime Number – C | C++ | Java | Python
Largest element in an array – C | C++ | Java | Python
Smallest element in an array – C | C++ | Java | Python
Reversing a Number – C | C++ | Java | Python
HCF of two numbers using Recursion – C | C++ | Java | Python
LCM of two numbers – C | C++ | Java | Python
Program to calculate length of the string using recursion- C | C++ | Java | Python
Print All Permutations of a String- C | C++ | Java | Python
Given an integer N the task is to print the F(N)th term.- C | C++ | Java | Python
Given a list arr of N integers, print sums of all subsets in it- C | C++ | Java | Python
Last non-zero digit in factorial- C | C++ | Java | Python
Given a positive integer N, return the Nth row of pascal’s triangle – C | C++ | Java | Python
Given an integer N representing the number of pairs of parentheses, the task is to generate all combinations of well-formed(balanced) parentheses – C | C++ | Java | Python
Find the Factorial of a number using recursion – C | C++ | Java | Python
Find all possible Palindromic partitions of the given String – C | C++ | Java | Python
Find all the N bit binary numbers having more than or equal 1’s than 0’s – C | C++ | Java | Python
Given a set of positive integers, find all its subsets – C | C++ | Java | Python
Given a string s, remove all its adjacent duplicate characters recursively – C | C++ | Python

Important Codes related to Arrays

Find Largest element in an array : C | C++ | Java | Python
Find Smallest Element in an Array : C | C++ | Java | Python
Find the Smallest and largest element in an array : C | C++ | Java | Python
Find Second Smallest Element in an Array : C | C++ | Java | Python
Calculate the sum of elements in an array : C | C++ | Java | Python
Reverse an Array : C | C++ | Java | Python
Sort first half in ascending order and second half in descending : C | C++ | Java | Python
Sort the elements of an array : C | C++ | Java | Python
Finding the frequency of elements in an array : C | C++ | Java | Python
Sorting elements of an array by frequency : C | C++ | Java | Python
Finding the Longest Palindrome in an Array : C | C++ | Java| Python
Counting Distinct Elements in an Array : C | C++ | Java| Python
Finding Repeating elements in an Array : C | C++ | Java | Python
Finding Non Repeating elements in an Array : C | C++ | Java | Python
Removing Duplicate elements from an array : C | C++ | Java | Python
Finding Minimum scalar product of two vectors : C | C++ | Java | Python
Finding Maximum scalar product of two vectors in an array : C | C++ | Java | Python
Counting the number of even and odd elements in an array : C | C++ | Java | Python
Find all Symmetric pairs in an array : C | C++ | Java | Python
Find maximum product sub-array in a given array : C | C++ | Java | Python
Finding Arrays are disjoint or not : C | C++ | Java | Python
Determine Array is a subset of another array or not : C | C++ | Java | Python
Determine can all numbers of an array be made equal : C | C++ | Java | Python
Finding Minimum sum of absolute difference of given array : C | C++ | Java | Python
Sort an array according to the order defined by another array : C | C++ | Java | Python
Replace each element of the array by its rank in the array : C | C++ | Java | Python
Finding equilibrium index of an array : C | C++ | Java| Python
Rotation of elements of array- left and right : C | C++ | Java| Python
Block swap algorithm for array rotation : C | C++ | Java| Python
Juggling algorithm for array rotation : C | C++ | Java | Python
Finding Circular rotation of an array by K positions : C | C++ | Java | Python
Balanced Parenthesis Problem : C | C++ | Java | Python

Operations on Strings

Check whether a character is a vowel or consonant : C | C++ | Java | Python
Check whether a character is a alphabet or not : C | C++ | Java | Python
Find the ASCII value of a character : C | C++ | Java | Python
Length of the string without using strlen() function : C | C++ | Java | Python
Toggle each character in a string : C | C++ | Java | Python
Count the number of vowels : C | C++ | Java | Python
Remove the vowels from a String : C | C++ | Java | Python
Check if the given string is Palindrome or not : C | C++ | Java | Python
Print the given string in reverse order : C | C++ | Java | Python
Remove all characters from string except alphabets : C | C++ | Java | Python
Remove spaces from a string : C | C++ | Java | Python
Remove brackets from an algebraic expression : C | C++ | Java | Python
Count the sum of numbers in a string : C | C++ | Java | Python
Capitalize the first and last character of each word of a string : C | C++ | Java | Python
Calculate frequency of characters in a string : C | C++ | Java | Python
Find non-repeating characters in a string : C | C++ | JAVA | Python
Check if two strings are Anagram or not : C | C++ | Java | Python
Replace a sub-string in a string: C | C++ | Java | Python
Replacing a particular word with another word in a string – C | C++ | Java | Python
Count common sub-sequence in two strings : C | C++ | Java | Python
Check if two strings match where one string contains wildcard characters : C | C++ | Java | Python
Print all permutations of a given string in lexicographically sorted order : C | C++ | Java | Python

Advanced Codes related to Arrays

Given an array which consists of only 0, 1 and 2. Sort the array without using any algorithm – C | C++ | Java | Python
Find the “Kth” max and min element of an array – C | C++ | Java | Python
Move all the negative elements to one side of the array – C | C++ | Java | Python
Find the Union and Intersection of the two sorted arrays. – C | C++ | Java | Python
Find Largest sum contiguous Subarray – C | C++ | Java | Python
Minimize the maximum difference between heights – C | C++ | Java | Python
Minimum no. of Jumps to reach the end of an array – C | C++ | Java | Python
Find duplicate in an array of N+1 Integers – C | C++ | Java | Python
Merge 2 sorted arrays without using extra space. – C | C++ | Java | Python
Kadane’s Algorithm – C | C++ | Java | Python
Merge Intervals – C | C++ | Java | Python
Count Inversion – C | C++ | Java | Python
Best time to buy and Sell stock – C | C++ | Java | Python
Find all pairs on integer array whose sum is equal to given number – C | C++ | Java | Python
Find if there is any subarray with sum equal to 0 – C | C++ | Java | Python
Find factorial of a Large Number – C | C++ | Java | Python
Find common elements In 3 sorted arrays – C | C++ | Java | Python
Rearrange the array in alternating positive and negative items with O(1) extra space – C | C++ | Java | Python
Given an array of size n and a number k, find all elements that appear more than ” n/k ” times. – C | C++ | Java | Python
Maximum profit by buying and selling a share atmost twice – C | C++ | Java | Python
Next Permutation – C | C++ | Java | Python
Find longest consecutive subsequence – C | C++ | Java | Python
Trapping Rain water problem – C | C++ | Java | Python
Chocolate Distribution problem – C | C++ | Java | Python
Smallest Subarray with sum greater than a given value – C | C++ | Java | Python
Three way partitioning of an array around a given value – C | C++ | Java | Python
Minimum no. of operations required to make an array palindrome – C | C++ | Java | Python
Median of 2 sorted arrays of equal size – C | C++ | Java | Python
Median of 2 sorted arrays of different size – C | C++ | Java | Python

Codes related to Matrix

Spiral traversal on a Matrix – C | C++ | Java | Python
Search an element in a matrix – C | C++ | Java | Python
Find median in a row wise sorted matrix – C | C++ | Java | Python
Find row with maximum no. of 1’s – C | C++ | Python
Print elements in sorted order using row-column wise sorted matrix – C | C++ | Java | Python
Find a specific pair in matrix – C | C++ | Java | Python
Rotate matrix by 90 degrees – C | C++ | Java | Python
Kth smallest element in a row-column wise sorted matrix – C | C++ | Java | Python
Common elements in all rows of a given matrix – C | C++ | Java | Python

Pattern Printing

           ****
           ****
           ****
           ****

Square Star Pattern

Difficulty – ★

Checkout code for this program –

C | Java | Python

Hollow Square Star Pattern

Difficulty – ★ and 1/2

Checkout code for this program –

C | Java | Python

           ****
            ****
             ****
              ****

Rhombus Star Pattern

Difficulty – ★★

Checkout code for this program –

C | Java | Python

           ******
           ******
           ******
           ******

Rectangle Star Pattern

Difficulty – ★

Checkout code for this program –

C | Java | Python

           ******
           *    *
           *    *
           ******

Hollow Rectangle Star Pattern

Difficulty – ★ and 1/2

Checkout code for this program –

C | Java | Python

           ******
            ******
             ******
              ******

Parallelogram Star Pattern

Difficulty – ★★

Checkout code for this program –

C | Java | Python

           ****
          ****
         ****
        ****

Mirrored Rhombus Star Pattern

Difficulty – ★★ and 1/2

Checkout code for this program –

C | Java | Python

Triangle Star Pattern

Difficulty – ★ and 1/2

C | Java | Python

              *
             ***
            *****
           *******

Pyramid Star Pattern

Difficulty – ★★

C | Java | Python

Hollow Pyramid Star Pattern

Difficulty – ★★

C | Java | Python

           *******
            *****
             ***
              *

Inverted Pyramid Star Pattern

Difficulty – ★★

C | Java | Python

Inverted Hollow Pyramid Star Pattern

Difficulty – ★★ and 1/2

C | Java | Python

Half Diamond Star Pattern

C | Java | Python

Half Diamond Star Pattern Inverted

C | Java | Python

             *
            ***
           *****
          *******
           *****
            ***
             *

Diamond Star Pattern

C | Java | Python

Number Pattern Printing Programs

Basic Square 1 Pattern

Checkout code for this program –

C | Java | Python

Basic Square incrementing Pattern

Checkout code for this program –

C | Java | Python

Internal varsity square Pattern

Checkout code for this program –

C | Java | Python

Basic Right Triangle Number Pattern

Checkout code for this program –

C | Java | Python

Basic Right Triangle Number Pattern (Inverted)

Checkout code for this program –

C | Java | Python

Basic incrementing Triangle Pattern initialised = 3

Checkout code for this program –

C | Java | Python

Basic incrementing Triangle Pattern(Inverted) initialised = 3

Checkout code for this program –

C | Java | Python

Basic double incrementing Triangle Pattern initialised = 3

Checkout code for this program –

C | Java | Python

Basic incrementing Diamond Pattern(Inverted) initialised = 3

Checkout code for this program –

C | Java | Python

Basic double incrementing Triangle Pattern initialised = 3

Checkout code for this program –

C | Java | Python

Basic incrementing Triangle Pattern(Inverted) initialised Mirrored = 3

Checkout code for this program –

C | Java | Python

Basic incrementing Diamond Pattern(Inverted Sandwich) initialised = 3

Checkout code for this program –

C | Java | Python

Basic double incrementing Triangle Pattern initialised Sandwich= 3

Checkout code for this program –

C | Java | Python

Basic incrementing Triangle Pattern(Inverted) initialised Mirrored Sandwich = 3

Checkout code for this program –

C | Java | Python

Number Star Mix Pattern

           1*2*3*4
           5*6*7*8
           9*10*11*12
           13*14*15*16

Basic incrementing Squared Number-Star Pattern

Checkout code for this program

C | Java | Python

           13*14*15*16
           9*10*11*12
           5*6*7*8
           1*2*3*4

Basic incrementing inverted Squared Number-Star Pattern

Checkout code for this program

C | Java | Python

          1*2*3*4
          9*10*11*12
          5*6*7*8
          13*14*15*16

Basic incrementing Squared Number-Star Pattern + Basic incrementing inverted Squared Number-Star Pattern (alternate)

Checkout code for this program

C | Java | Python

          1*2*3*4
          9*10*11*12
          13*14*15*16
          5*6*7*8

Basic incrementing Squared Number-Star Pattern + Basic incrementing inverted Squared Number-Star Pattern (alternate)

Type 2

Checkout code for this program

C | Java | Python

          1*2*3*4
          9*10*11*12
          17*18*19*20
          13*14*15*16
          5*6*7*8

Basic incrementing Squared Number-Star Pattern + Basic incrementing inverted Squared Number-Star Pattern (alternate)

Type 3

Checkout code for this program

C | Java | Python

          4*3*2*1
          12*11*10*9
          8*7*6*5
          16*15*14*13

Basic incrementing Squared Number-Star Pattern Mirrored + Basic incrementing inverted Squared Number-Star Pattern Mirrored (alternate)

Checkout code for this program

C | Java | Python

Basic incrementing Triangle Pattern

Checkout code for this program

C | Java | Python

Basic incrementing Triangle Pattern

Checkout code for this program

C | Java | Python

Basic incrementing Triangle Pattern + Inverted (Mix)

Checkout code for this program

C | Java | Python

Basic incrementing mirrored Triangle Pattern

Checkout code for this program

C | Java | Python

Basic incrementing inverted mirrored Triangle Pattern

Checkout code for this program

C | Java | Python

Basic incrementing Triangle Pattern + Inverted (Mix)

Checkout code for this program

C | Java | Python

Basic Diamond Number Star Pattern

Checkout code for this program

C | Java | Python

Basic Diamond Number Star Pattern (Sandwich)

Checkout code for this program

C | Java | Python

Basic Diamond Number Star Pattern (Sandwich Inverted)

Checkout code for this program

C | Java | Python

Basic Diamond Number Star Pattern initialised

Checkout code for this program

C | Java | Python

Basic Diamond Number Star Pattern (Sandwich)

Checkout code for this program

C | Java | Python

Basic Diamond Number Star Pattern (Sandwich Inverted)

Checkout code for this program

C | Java | Python

Few more pattern programs

Program for Pyramid star pattern
Program for Pyramid number pattern
Program for Palindromic Pyramid Pattern – Java
Program for Diamond star pattern
Program for Diamond number pattern
Program for Floyd’s Triangle – Java
Program for Pascal triangle – Java
Program to Check array similarity
Program for Square sum
Program for Longest palindrome in the array

23 comments on “Top 100 Codes”

Katta
Im so glad for visiting this site 🥲🫡

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Hritik S
Sir or Mam how can built logic to solve these question ? Please explain it

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PrepInsta Support
Hey, we recommend you to practice as much coding questions as you can, this will help you out to develop logic.💕

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JAI KRISHNAN
super website to attend the questions .Thank you for giving this platform to all.

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PrepInsta Support
Hey there,
Thanks for your feedback, it means alot.

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Yasmin Shaik
Hi sir iam in 3rd year i can’t know how to prepare for placenta can you please help me how to prepare for placements

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PrepInsta Support
Hey there, Kindly message us at Whatsapp number 8448440710, Our expert mentors will guide you further precisely🙌.

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AISHIKA
Will these questions be enough to crack service base companies?

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PrepInsta Support
Hi Aishika,
These questions will be enough but you can still practice dedicated company based Coding Questions.

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Mokara
Yes

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PrepInsta Support
❤❤

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AISHIKA
Will these questions be enough to crack product base companies?

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PrepInsta Support
Hi Aishika,
Yes these questions will be enough but we will advice to practice Intermediate Coding Questions as well.

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Suman Dolai
hii can i ask few questions

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PrepInsta Support
Hey there, Thanks for commenting and feel free to ask your queries🙌

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Parth
Nice

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BARATH
Will these questions be enough to crack 8+LPA companies.

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PrepInsta Support
Yes, these are good enough. But for packages > 6LPA also do DSA, you can refer https://prepinsta.com/data-structures/

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Ramya
Civil war 1 code

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Kadali
Hi Sir,Now I am in 3rd year still I don’t know how to get a placement.Can you please help me to get a placement.

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PrepInsta Support
Hey there, Don’t worry. We are right here to help you. Kindly cal us on 8448440710 or text us on 8287659510 for guidance. Our team would be more than glad to help you.

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The
I think these are enough to crack coding round, thankyou prepinsta
PrepInsta Support
We are glad to see that ❤

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Top 100 Codes

PrepInsta Top 100 Codes

Getting Started

Working with Numbers

Codes for Recursion

Important Codes related to Arrays

Operations on Strings

Advanced Codes related to Arrays

Codes related to Matrix

Pattern Printing

Number Pattern Printing Programs

Number Star Mix Pattern

Few more pattern programs

23 comments on “Top 100 Codes”

30+ Companies are Hiring

Unlock this article for Free, by logging in

Top 100 Codes

PrepInsta Top 100 Codes

Getting Started

Working with Numbers

Codes for Recursion

Important Codes related to Arrays

Operations on Strings

Advanced Codes related to Arrays

Codes related to Matrix

Pattern Printing

Number Pattern Printing Programs

Number Star Mix Pattern

Few more pattern programs

23 comments on “Top 100 Codes”

30+ Companies are Hiring

Unlock this article for Free,
by logging in