Parenthesis Checking

#include<iostream>
#include  <bits/stdc++.h>
#include<string>
#define MAX 100
#include"stack.h"
using namespace std;

class Paranthesis{
    Stack s;
    char str[MAX];
public:
    void check(){
        cout<<"\nEnter # after expression(At the end)\n";
        cout<<"\nEnter Expression: ";
        cin.getline(str,MAX,'#');
        char ch;
        bool flag=0;
        for(int i=0;str[i]!='\0';i++)
        {
            if(str[i]=='(' || str[i]=='[' || str[i]=='{')
                s.push(str[i]);
            if(str[i]==')'||str[i]==']'||str[i]=='}')
            {
            if(s.isEmpty()){
                flag = 1; break;}
            ch=s.pop();
                if((str[i]==')'&& ch!='(') ||(str[i]==']'&& ch!='[')||(str[i]=='}'&& ch!='{'))
                {
                    cout<<"\nNot parenthesized At "<<i<<" = "<<str[i];
                    flag=1;
                    break;
                }
            }
        }
        if(s.isEmpty()==1 && flag==0)
            cout<<"\nExpresseion is Well Parenthesized.";
        else
            cout<<"\nExpression is not Well Parenthesized.";
    }

};

int main(){
    Paranthesis p;
    p.check();

    return 0;
}