Mayur.cpp

#include <bits/stdc++.h>
using namespace std;
int prec(char c)
{
    if (c == '^')
        return 3;
    else if (c == '/' || c == '*')
        return 2;
    else if (c == '+' || c == '-')
        return 1;
    else
        return -1;
}
void infixToPostfix(string s)
{

stack<char> st;
    string result;

    for (int i = 0; i < s.length(); i++) {
        char c = s[i];

        if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')
            || (c >= '0' && c <= '9'))
            result += c;
        else if (c == '(')
            st.push('(');

        else if (c == ')') {
            while (st.top() != '(') {
                result += st.top();
                st.pop();
            }
            st.pop();
        }

        else {
            while (!st.empty()
                && prec(s[i]) <= prec(st.top())) {
                result += st.top();
                st.pop();
            }
            st.push(c);
        }
    }
    while (!st.empty()) {
        result += st.top();
        st.pop();
    }

    cout << result << endl;
}
int main()
{
    string exp;
    std::cout<<"Enter the String to be converted:\n";
    std::cin>>exp;
    infixToPostfix(exp);
    return 0;
}