Dynamic Memory Allocation in C using Calloc

January 19, 2023

Dynamic memory allocation using calloc in C :

On this page we will discuss about dynamic memory allocation using calloc function in C programming language. calloc( ) is used contiguous block of memory at run time those memory block are initialized to zero. calloc() return the base address of allocated memory on successful allocation. calloc function is similar as malloc function.

Dynamic memory allocation using calloc function

The calloc function is used to allocate multiple memory block of same size in contiguous manner at run time .That is why calloc( ) is also know as contiguous allocation.The only difference between calloc and malloc is of intialization.In calloc the each memory block when allocated is initialized with zero.
The calloc ( ) is predefined function which comes under stdlib.h .It returns a NULL pointer in case of failure of memory allocation. Calloc function has two parameter first is number of blocks and second is size of each block.
On successful allocation of memory a pointer is returned containing the base address of allocated memory. Otherwise in case of failure of memory allocation NULL pointer is returned.

Syntax: ptr = (cast_type *) calloc (a, s);
(where ‘a’ is number of blocks and s is size of each memory block.)

Example:

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Note: To avoid memory leak we must deallocate the return pointer with free() or realloc().

Implementation of dynamic memory allocation using calloc :

Run

#include <stdio.h>
#include <stdlib.h>

int main ()
{

  int *ptr;			//pt to hold base address of memory block allocated
  int a, j;


  a = 5;			//number of elements in block
  printf ("Enter number of elements: %d\n", a);

  ptr = (int *) calloc (a, sizeof (int));	//syntax of calloc
  if (ptr == NULL)
    {
      printf ("Memory not allocated.\n");
      return 0;
    }

  printf ("Memory allocated successful.\n");

  for (j = 0; j < a; ++j)
    {
      ptr[j] = j + 1;
    }

  printf ("The elements of the array are: ");
  for (j = 0; j < a; ++j)
    {
      printf ("%d, ", ptr[j]);
    }


  return 0;
}

Output:

Enter number of elements: 5
Memory allocated successful.
The elements of the array are: 1, 2, 3, 4, 5

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