i want the benefit but it just show the 0

// saham.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<queue>
#include<iostream>
using namespace std;

int main()
{

  queue<int> boughtn ;
  queue<int> soldn ;
  queue<int> boughtp ;
  queue<int> soldp ;
  int boughtnum ;
  int boughtprice ;
  int soldnum ;
  int soldprice ;
  int benefit = 0 ;
  cout << "Please enter number of bought stocks (enter 0 to end):\n" << endl ;
 
  do
  {
    cin >> boughtnum ;
    boughtn.push (boughtnum);

  }
  while (boughtnum);

   cout << "Please enter price of bought stocks (enter 0 to end):\n" << endl ;
 
  do
  {
    cin >> boughtprice ;
    boughtp.push (boughtprice);
  }
  while (boughtprice);

  cout << "Please enter number of sold stocks (enter 0 to end):\n" << endl ;
 
  do
  {
    cin >> soldnum ;
    soldn.push (soldnum);
  }
  while (soldnum);

   cout << "Please enter price of sold stocks (enter 0 to end):\n" << endl ;
 
  do
  {
    cin >> soldprice ;
    soldp.push (soldprice);
  }
  while (soldprice);
  

  while ( ( !boughtn.empty() ) & ( !soldn.empty() ) )
  {
	   boughtn.front();
	   boughtn.pop() ;
	   boughtp.front();
	   boughtp.pop() ;
	   soldp.front();
	   soldn.pop() ;
	   soldn.front();
	   soldp.pop() ;
	  
	
	  //benefit += soldn.pop() * ( soldp.pop() - boughtp.front());
	  boughtnum = boughtnum - soldnum ; 
	  benefit = benefit + ( boughtprice - soldprice ) * soldnum ;
 
   cout << "The benefit is " << benefit << endl ;
  }

    


}