#include <iostream>
#include <stack>
using namespace std;
// funtion to check if character is operator or not
bool isOperator(char x) {
switch (x) {
case '+':
case '-':
case '/':
case '*':
return true;
}
return false;
}
// Convert prefix to Postfix expression
string preToPost(string pre_exp) {
stack<string> s;
// length of expression
int length = pre_exp.size();
// reading from right to left
for (int i = length - 1; i >= 0; i--) {
// check if symbol is operator
if (isOperator(pre_exp[i])) {
// pop two operands from stack
string op1 = s.top(); s.pop();
string op2 = s.top(); s.pop();
// concat the operands and operator
string temp = op1 + op2 + pre_exp[i];
// Push string temp back to stack
s.push(temp);
}
// if symbol is an operand
else {
// push the operand to the stack
s.push(string(1, pre_exp[i]));
}
}
// stack contains only the Postfix expression
return s.top();
}
// Driver Code
int main() {
string pre_exp;
cout << "Prefix expression: ";
cin >> pre_exp;
//string pre_exp = "*-A/BC-/AKL";
cout << "Postfix : " << preToPost(pre_exp);
return 0;
}
