int compare(char *s1,char *s2)
{
int s1_len,s2_len;
s1_len=strlen(s1);
s2_len=strlen(s2);
switch (s1_len-s2_len){
case -1:return unequal(s2,s1);
case 1:return unequal(s1,s2);
case 0:return equal(s1,s2);
default:return 0;
}
}
int main(){
std::string s1 = "(abc)", s2 = "(abc";
std::string target;
if(auto check = unequal(s1.find(')'), s1.npos))
std::copy(s1.begin(), s1.begin() + check.value, std::back_inserter(target));
std::cout << target;
}
