#include <stdio.h>
#include<stdlib.h>
#define NULL 0
main()
{
    char *buffer;
    /* Allocating memory */
if((buffer = (char *)malloc(10)) == NULL)
    {
        printf(“malloc failed.\n”);
        exit(1);
    }
    printf(“Buffer of size %d created \n”,_msize(buffer));
    strcpy(buffer, “HYDERABAD”);
    printf(“\nBuffer contains: %s \n “, buffer);
    /* Realloction */
if((buffer = (char *)realloc(buffer, 15)) == NULL)
    {
        printf(“Reallocation failed. \n”);
        exit(1);
    }
    printf(“\nBuffer size modified. \n”);
    printf(“\nBuffer still contains: %s \n”,buffer);
    strcpy(buffer, “SECUNDERBAD”);
    printf(“\nBuffer now contains: %s \n”,buffer);
/* Freeing memory */

free(buffer);
 }

Output
Buffer of size 10 created
Buffer contains: HYDERABAD
Buffer size modified
Buffer still contains: HYDERABAD
Buffer now contains: SECUNDERABAD