Programming in C not C++

/* What does this program do? */#include void mystery1(char *s1, const char *s2);//prototype int main(void) {char stringl[80];//create char array char string2[80];//create char array printf("Enter two strings: "); scanf("%79s %79s", string1, string2); mystery1(string1, string2); printf("%s ", string1); return 0;//indicate successful termination.//end main//What does this function do? void mystery1(char *s1, const char *s2) {while (*s1 != '\0') s1++; for (; *s1 = *s2; s1++, s2++) {;//empty statement.}//end for//end function mystery1