//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*/