// Program to convert a prefix expression to postfix expression
// Prefix expression : An expression in which the operator appears before the operands. 
// Postfix expression : An expression in which the operator appears after the operands. 



// Alogorithm
// To convert prefix to postfix expression we follow steps given below:
// Step 1. If the symbol is an operand, push it to the stack
// Step 2. If symbol is an operator then pop top two elements from stack
// Step 3. Then push an expression by concatenating (+op1+op2+symbol)
// Step 4. At last return the top element of stack as postfix expression



// CODE:
#include<bits/stdc++.h>
using namespace std;

// Function to convert prefix to postfix expression
string prefix_to_postfix(string prefix)
{
    stack<string> s;
    // length of prefix expression
    int l=prefix.length();
  
    // Iterating through the Prefix expression from right to left
    for(int i=l-1;i>=0;i--){
        // if the symbol is an operand, push it to the stack
        if(prefix[i]>='a' && prefix[i]<='z'||prefix[i]>='A' && prefix[i]<='Z'){
            s.push(string(1,prefix[i]));
        }

        // if symbol is an operator
        else
        { 
            string op1=s.top();
            s.pop();
            string op2=s.top();
            s.pop();
            string temp=(op1+op2+prefix[i]);
            s.push(temp);
        }
    }
    // returning element at top of stack
    return s.top();
}

// MAIN FUNCTION
int main()
{
  string exp;
  cout<<"Enter expression: ";
  cin>>exp;
  cout<<"Prefix to Postfix expression is: "<<prefix_to_postfix(exp);
}


// OUTPUT:
// Enter expression: *-a/bc-/akl
// Prefix to Postfix expression is: abc/-ak/l-*