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. :confused:

Code:

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# 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;
 }

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Ok, where to start;

This line is not needed:

Code:

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number_of_books_purchased = number_of_books_purchased;

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This line is not valid:

Code:

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category = old, new, temporary;

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You need to reread up on char's


These lines:

Code:

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

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


This line:

Code:

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costOfBooksPurchased = number_of_books_purchased *
                                                  bookPrice;

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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.

You cannot use the keyword new as a variable name.

initialize your variables.

You can not read a string into a single char.

You only ask how many books one time, yet your calculations imply there was more than one entry.
Maybe you need multiple questions , or some sort of loop. I'm not sure exactly what you're trying to do.

Code:

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cout << "Enter the number of old books purchased:";
cin >> num_old_books;
cout << "Enter the number of new books purchased:";
cin >> num_new_books;
......

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Then display results for each category as well as the totals