Convert Prefix Expression to Infix Expression in C++.

#include<bits/stdc++.h>

#include<string>

#include<stdio.h>

#include<stdlib.h>

/*prefix to infix*/

using namespace std;

string convertPreToIn(string pre)

{

    stack<string> stk;

    for(int i=pre.size()-1; i>=0; i--)

    {

        if(pre[i]=='+' || pre[i]=='-' ||pre[i]=='*' ||pre[i]=='/' || pre[i]=='^')

        {

            string a = stk.top();

            stk.pop();

            string b = stk.top();

            stk.pop();

            string t = "(" + a +   string(1, pre[i]) + b +")";

            stk.push(t);

        }

        else

        {

            stk.push(string(1, pre[i]));

        }

    }

    return stk.top();

}

int main()

{

    string pre;

    cout<<"
Enter Prefix: ";

    cin>>pre;

    cout<<"
Infix: "<<convertPreToIn(pre)<<endl;

}