Infix_to_Postfix

#include <iostream>
#include <stack>
#include <string>

using namespace std;


int main() {
    stack <char> S;
    char ch;
    string line;

    getline(cin, line);

    for (int i = 0; line[i]; i++) {
        if (line[i] == ' ')
            continue;
        else if (line[i] == '(' || line[i] == '+' || line[i] == '-' || line[i] == '*' || line[i] == '/' || line[i] == '%' || line[i] == '^')
            S.push(line[i]);
        else if (line[i] == ')') {
            while (S.top() != '(') {
                cout << S.top() << " ";
                S.pop();
            }
            S.pop();
        }
        else
            cout << line[i] << " ";
    }
    while (!S.empty()) {
        ch = S.top();
        if (ch != '(')
            cout << ch << " ";
        S.pop();
    }
    cout << endl;

    return 0;
}