parseValidBracketswithstack

#include <iostream>
#include <stack>
#include <sstream>
#include <cassert>
using namespace std;

struct node
{
    char sym;
    int pos;
};
bool isOpenBracket(const char & c) {
    return  c == '{' || c == '[' || c == '(';
}
bool isClosedBracket(const char & c) {
    return  c == '}' || c == ']' || c == ')';
}
bool isClosedBracketGood(const char  l, const char  r) {
    return (l == '{' && r == '}') || (l == '[' && r == ']') || (l == '(' && r == ')');
}
int checkBracket(istream & s) {
    char c;
    int pos = 1;
    std::stack <node> stk;
    while (s >> c ) {
        if (isOpenBracket(c)) stk.push({c, pos});
        else if (isClosedBracket(c)) {
            if (stk.empty()) return pos;
            node x = stk.top();
            if (isClosedBracketGood(x.sym, c))
                stk.pop();
            else
                return pos;
        }
        pos++;
    }
    return stk.empty()? 0 : stk.top().pos;
}
int check(const char *s) {
   istringstream iss(s);
    return checkBracket(iss);
}
void test1() {
    assert (check("([](){([])})") == 0);
    assert (check("()[]}") == 5);
    assert (check("{{[()]]") == 7);
    assert (check("{{{[][][]") == 3);
    assert (check("{*{{}") == 3);
    assert (check("[[*") == 2);
    assert (check("{*}") == 0);
    assert (check("{{") == 2);
    assert (check("{}") == 0);
    assert (check("") == 0);
    assert (check("}") == 1);
    assert (check("*{}") == 0);
    assert (check("{{{**[][][]") == 3);
}
int main()
{
    //test1();
    int pos = checkBracket(cin);
    if  (pos == 0) std::cout << "Success";
    else std::cout << pos;
    return 0;
}