Thread: Program output not right

I need some help. My output is all wrong. I am trying to get output of cost of books purchased (will be different amounts according to category), sales tax due, total due, category and number of books purchased. I have only been doing C++ for about a month now and I am very green to say the least.

Code:

# include <iostream>
# include <iomanip>
# include <cmath>

using namespace std;

char old;
char new;
char temporary;


int main()
 {
         //declare variables
	    char category;
	    double costOfBooksPurchased;
	    double salesTaxDue;
	    double totalDue;
	    int number_of_books_purchased;
                    double oldBookPrice;
                    double newBookPrice;
                    double temporaryBookPrice;
	    double bookPrice;


  cout << fixed << showpoint << setprecision (2);

  cout << "Enter the number of books purchased: ";
  cin >> number_of_books_purchased;
  cout << endl;

  cout << "Enter the category: old, new, temporary: ";
  cin >> category;
  cout << endl;

  number_of_books_purchased = number_of_books_purchased;

  category = old, new, temporary;


  if (number_of_books_purchased >=6)
       {
             temporaryBookPrice = number_of_books_purchased * 50;
             newBookPrice = number_of_books_purchased * 35;
             oldBookPrice = number_of_books_purchased * 20;
        }
  else 
       {
            temporaryBookPrice = number_of_books_purchased * 45;
            newBookPrice = number_of_books_purchased * 30;
            oldBookPrice = number_of_books_purchased * 15;
        }

        
        bookPrice = temporaryBookPrice;
        bookPrice = newBookPrice;
        bookPrice = oldBookPrice;

        costOfBooksPurchased = number_of_books_purchased *
                                                  bookPrice;

        salesTaxDue = costOfBooksPurchased * .04;

        totalDue = costOfBooksPurchased +  salesTaxDue;

  cout << "The number_of_books_purchased = " <<
                number_of_books_purchased << endl;

  cout << "The category = " << category << endl; 

  cout << "The costOfBooksPurchased = $" <<   
               costOfBooksPurchased << endl;

  cout << "The salesTaxDue = $" << salesTaxDue << endl;

  cout << "The totalDue = $" << totalDue << endl;
        
  return 0;
 }

Ok, where to start;

This line is not needed:

Code:

number_of_books_purchased = number_of_books_purchased;

This line is not valid:

Code:

category = old, new, temporary;

You need to reread up on char's


These lines:

Code:

        bookPrice = temporaryBookPrice;
        bookPrice = newBookPrice;
        bookPrice = oldBookPrice;

The value of bookPrice will only end up holding the value of oldBookPrice.


This line:

Code:

costOfBooksPurchased = number_of_books_purchased *
                                                  bookPrice;

Is actually faulty becuse in your If-Else statements you already multiplied the number of books purchased times the price. So you are now multiplying number_of_books_purchased by the bookPrice, what was already previously the same calculation.