/* Using realloc() to change memory allocation. */

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

main()
{
    char buf[80], *message;

     /* Input a string. */

     puts("Enter a line of text.");
     gets(buf);

     /* Allocate the initial block and copy the string to it. */

     message = realloc(NULL, strlen(buf)+1);
     strcpy(message, buf);

     /* Display the message. */

     puts(message);

     /* Get another string from the user. */

     puts("Enter another line of text.");
     gets(buf);

     /* Increase the allocation, then concatenate the string to                  
        it. */

     message = realloc(message,                          
     (strlen(message)+strlen(buf)+1));
     strcat(message, buf);

     /* Display the new message. */
     puts(message);
     return(0);
}