balanced parentheese.cpp

// balanced parentheses
# include<bits/stdc++.h>
using namespace std;

bool arePair(char open, char close){
    if(open == '(' && close == ')')
        return true;
    else if(open == '{' && close == '}')
        return true;
    else if(open == '[' && close == ']')
        return true;
    return false;
}

bool areBalanced(string exp){
    stack<char>s;
    for(size_t i = 0; i < exp.length(); i++){
        if(exp[i] == '(' || exp[i] == '{' || exp[i] == '[')
            s.push(exp[i]);
        else if(exp[i] == ')' || exp[i] == '}' || exp[i] == ']'){
            if(s.empty() || !arePair(s.top(), exp[i]))
                return false;
            else
                s.pop();
        }
    }
    return s.empty() ? true : false;
}

int main(){
    string expression;
    cout << "Enter an expression: ";
    cin >> expression;
    if(areBalanced(expression))
        cout << "Balanced" << endl;
    else
        cout << " Not balances" << endl;
}