test case incorrect for paranthesis checker code. For '(()' output sould be 'not balanced' but i'm getting 'balanced'

Question

Given an expression string exp. Examine whether the pairs and the orders of “{“,”}”,”(“,”)”,”[“,”]” are correct in exp. For example, the program should print 'balanced' for exp = “[()]{}{[()()]()}” and 'not balanced' for exp = “[(])”

Input

The first line of input contains an integer T denoting the number of test cases. Each test case consists of a string of expression, in a separate line.

Output

Print 'balanced' without quotes if the pair of parenthesis is balanced else print 'not balanced' in a separate line.

Constraints

1 ≤ T ≤ 100
1 ≤ |s| ≤ 105

Example

Input:

3
{([])}
()
([]

Output

balanced
balanced
not balanced

#include <iostream>
#include <cstring>
#include <stack>
using namespace std;

int main() {
    //code
    int t;cin>>t;
    while(t--) {
        string s;
        stack<char> st;
        int i=0,flag =1;
        getline(cin,s);
        int n = s.size();
        while(s[i] != '\0') {
            if((s[i] == '{') || (s[i] == '[') || (s[i] == '(')) {
                st.push(s[i]);
            }
            else if(!st.empty() && ((st.top() == '{' && s[i] == '}') || 
            (st.top() == '[' && s[i] == ']') || (st.top() == '(' && s[i] == ')'))) st.pop();
            else {
                flag = 0;
                break;
            }
            i++;
        }
        (st.empty() && flag) ? cout<<"balanced\n" : cout<<"not balanced\n";
    }
    return 0;
}

This program is simple enough that you can step through the failing test case with a debugger and verify your assumptions. — Botje, May 14 '20 at 08:45
I can reproduce it, `())` should result in "not balanced" and indeed it results in "not balanced": https://godbolt.org/z/Mn2hwr. There is a small misunderstanding somewhere... — 463035818_is_not_a_number, May 14 '20 at 08:54
I ran it and `(()` returned `"not balanced"`. I had to include `` for it to compile, and I hate the print-out line, but apart from that ... — Neil Gatenby, May 14 '20 at 09:11

score 0 · Accepted Answer · answered May 14 '20 at 09:09

Stepping through your code with a debugger, the first time through the loop your string is empty.

This is because cin >> t stops reading at the newline character of the first line, and the first getline(cin, s) line receives an empty string.

Simply call getline(cin, dummy_string) after cin >> t to read the rest of the line, or switch your loop to use cin >> s instead.

test case incorrect for paranthesis checker code. For '(()' output sould be 'not balanced' but i'm getting 'balanced'

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