45.To concatinate two strings

1 .Using function

#include <stdio.h>

#include <string.h>

int main()

{

   char a[100], b[100];

   printf("Enter the first string\n");

   gets(a);

   printf("Enter the second string\n");

   gets(b);

   strcat(a,b);

   printf("String obtained on concatenation is %s\n",a);

   return 0;

}

2.Without using function

#include <stdio.h>

void concatenate_string(char*, char*);

int main()

{

    char original[100], add[100];

    printf("Enter source string\n");

    gets(original);

    printf("Enter string to concatenate\n");

    gets(add);

    concatenate_string(original, add);

    printf("String after concatenation is \"%s\"\n", original);

    return 0;

}

void concatenate_string(char *original, char *add)

{

   while(*original)

      original++;

   while(*add)

   {

      *original = *add;

      add++;

      original++;

   }

   *original = '\0';

}