The calculation in my c++ code is wrong. Please help.

Question

I'm having a problem with getting the right calculation for the subtotal of each ticket. I'm currently getting this type of result:

Premium Tickets: $ 80.00 x 2 = $ 5242800
Regular Tickets: $ 40.00 x 2 = $ 40
Sales Tax (9.25): $484962.72

What am I doing wrong? C++ code:

#include <iostream>
#include <iomanip>

using namespace std;

int main ()
{
   cout << setprecision(2) << fixed << showpoint;
   
   const float SALES_TAX = 0.0925;

   float premiumTicket = 80;
   float regularTicket = 40;

   int premTicket;
   int regTicket;
   
   premTotal = premiumTicket * premTicket;
   regTotal = regularTicket * regTicket;

   float subTotal = premTotal + regTotal;
   float tax = subTotal * SALES_TAX;
   float total = subTotal + tax;

   cout << "How many Premium Tickets? ($80): " << setw(4) << endl;
   cin >> premTicket;
   cout << "How many Regular Tickets? ($40): " << setw(4) << endl;
   cin >> regTicket;
   cout << "Premium Tickets: " << setw(4) << " $ " << setw(4) << premiumTicket << " x " << premTicket << " = " << setw(4) << " $ " << setw(4) << premTotal << endl;
   cout << "Regular Tickets: " << setw(4) << " $ " << setw(4) << regularTicket << " x " << regTicket << " = " << setw(4) << " $ " << setw(4) << regTotal << endl;
   cout << "Sales Tax (9.25):    $" << setw(4) << tax << endl;
   
   return 0;
}

Answer 1

Your problem is that you use the values of premTicket and regTicket for calculations before you'd ask the user to provide these values.

The fix is to ask the user first, then do the calculations with the provided input:

#include <iostream>
#include <iomanip>

using namespace std;

int main ()
{
   cout << setprecision(2) << fixed << showpoint;
   
   const float SALES_TAX = 0.0925;

   float premiumTicket = 80;
   float regularTicket = 40;

   int premTicket;
   int regTicket;

   cout << "How many Premium Tickets? ($80): " << setw(4) << endl;
   cin >> premTicket;
   cout << "How many Regular Tickets? ($40): " << setw(4) << endl;
   cin >> regTicket;
   
   int premTotal = premiumTicket * premTicket;
   int regTotal = regularTicket * regTicket;

   float subTotal = premTotal + regTotal;
   float tax = subTotal * SALES_TAX;
   float total = subTotal + tax;

   cout << "Premium Tickets: " << setw(4) << " $ " << setw(4) << premiumTicket << " x " << premTicket << " = " << setw(4) << " $ " << setw(4) << premTotal << endl;
   cout << "Regular Tickets: " << setw(4) << " $ " << setw(4) << regularTicket << " x " << regTicket << " = " << setw(4) << " $ " << setw(4) << regTotal << endl;
   cout << "Sales Tax (9.25):    $" << setw(4) << tax << endl;
   
   return 0;
}