C Programming

Program 66) Write a program to store a character string in a block of memory space created by malloc and then modify the same to store a larger string.

The output illustrates that the original buffer size obtained is modified to contain a larger string. Note that the original contents of the buffer remains same even after modification of the original size.

                                        PROGRAM

#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, "HYDRABAD") ;
     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, "SECUNDERABAD") ;
    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: HYDRABAD
                       Buffer now contains: SECUNDERABAD