How to solve ONP problem?

help
1

how to solve ONP problem?

2

You can solve any of these kinds of problems with the help of stack data structure. I write the code for this problem so take a look and if you don’t get anything, I will try to help.

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

int main() {
	int t;cin>>t;
	while(t--){
	    string s;cin>>s;
	    stack<char> stop;
	    string res="";
	    for(int i=0;i<s.length();i++){
	        if(s[i]=='+' || s[i]=='-' || s[i]=='*' || s[i]=='/' || s[i]=='^'){
	            stop.push(s[i]);
	        }
	        else if(s[i]==')'){
	            res+=stop.top();
	            stop.pop();
	        }else if(s[i]!='('){
	            res+=s[i];
	        }
	    }
	    
	    cout<<res<<'\n';
	    
	}
	return 0;
}