C/string.h/strcat

strcat: concatenates a copy of *str2 to *str1 and terminates *str1 with a null

<source lang="cpp">

//Declaration: char *strcat(char *str1, const char *str2); //Return: returns *str1.

 #include <stdio.h>
 #include <string.h>
 int main(void)
 {
   char s1[80], s2[80];
   printf("s1:");
   gets(s1);
   printf("s2:");
   gets(s2);
   strcat(s2, s1);
   printf(s2);
   return 0;
 }
        

/* s1:s s2:2 2s*/

      </source>