Why does my "while" loop execute no matter what i enter?

/*********************************************************
** Purpose: Asks the user for cable package they bought **
** and the amount of hrs they used and //tells them     **
** their monthly bill                                   **
**********************************************************/                                        




#include <iostream>
#include <iomanip>

using namespace std;

int main()
{
    //Defining variables
    double hours_over;  //Amount of hrs the user went over their monthly allottment
    double extra_pay;   //Extra bill amount for going over monthly hrs allotted
    double monthly_bill;  //Monthly bill the user will pay
    int hours;          // How many hours the user used during the month
    char package;       //The package the user chose

    //Getting the package the user bought
    cout << "Your monthly subscription bill is based on your package.";
    cout << "\n\nWhat package did you buy? Enter A, B or C: ";
    cin >> package;

    //Validating user input-must enter A, B or C
    while (package != 'A' || package != 'B' || package != 'C')
    {
      cout << "\nPlease enter A, B or C(capitalized).";
      cout << "\n\nWhat package did you buy?: ";
      cin >> package;
    }

    //Getting hours the user used during month
    cout << "How many hours did you use?: ";
    cin >> hours;

    //Validating user input-hrs cant exceed 744
    while (hours > 744)
    {
      cout << "I'm sorry but your monthly usage cannot exceed 744 hrs.";
      cout << "\nPlease enter another number.";
      cout << "How many hours did you use?: ";
      cin >> hours;
    }

    //Fixing decimal place of answers
    cout << setprecision(2) << fixed << showpoint << endl;

    //Switch statement-go to the packag开发者_开发问答e the user bought
    switch (package)
    {
       case 'A':
            if (hours > 10)
            {
                      hours_over=hours-10;
                      extra_pay=hours_over*(2.00);
                      monthly_bill=9.95+extra_pay;

                      cout << "Your monthly bill is: $" << monthly_bill << endl;
            }
            else
            {
                 cout << "Your monthly bill is: $9.95";
            }
            break;

       case 'B':
            if (hours > 20)
            {
                      hours_over=hours-20;
                      extra_pay=hours_over;
                      monthly_bill=14.95+extra_pay;

                      cout << "Your monthly bill is: $" << monthly_bill << endl;
            }
            else
            {
                 cout << "Your monthly bill is: $14.95";
            }
            break;

       case 'C':
            cout << "Your monthly bill is: $19.95";
            break;

       default:
            break;   
    }

cin.get();
return 0;
}

Your test for A, B, or C is wrong

 while (package != 'A' || package != 'B' || package != 'C')

should be

 while (package != 'A' && package != 'B' && package != 'C')

Consider your expression:

while (package != 'A' || package != 'B' || package != 'C') {

Let package have the value 'A'.

This evaluates to

false || true || true

which is of course true.

This line always evaluates to true:

while (package != 'A' || package != 'B' || package != 'C')

it should probably be:

while (package != 'A' && package != 'B' && package != 'C')

You should be checking to see if cin has been able to stream a value of the desired type, ala if (cin >> my_int), then using std::cin.clear() after an erroneous input before getting them to reenter the value. Otherwise, garbage values like say some text input that can't be converted to an int leave std::cin in an error state and the next std::cin >> xxx isn't even attempted.

The "while" will only loop when you want it to, but the "if" will always fire; is that what you mean? The "if" concerning A, B, or C always fires because you've used "||" meaning "or" to link conditions. It is always true, for any value of your variable, that it's not A, or not B, or not C!

First of all, this code:

//Validating user input-must enter A, B or C
if (package != 'A' || package != 'B' || package != 'C')
{
  cout << "\nPlease enter A, B or C(capitalized).";
  cout << "\n\nWhat package did you buy?: ";
  cin >> package;
}

won't work, because (1) you're comparing a string (package) to characters, and (2) you're using || (or) instead of && (and). Also (3) you probably want "while" instead of "if".

The while loop worked fine for me.

cin >> package;
//Validating user input-must enter A, B or C
while (package != 'A' || package != 'B' || package != 'C')
{
  cout << "\nPlease enter A, B or C(capitalized).";
  cout << "\n\nWhat package did you buy?: ";
  cin >> package;
}

What if the package value is B entered inside the loop. It satisfies the first condition package != 'A' and since it is an OR operation after it( true || false || true leads to true), loop enters. You should use && instead. So, change

 while (package != 'A' && package != 'B' && package != 'C')
 {
     // .....
 }