Here is the problem specification: An Internet service provider has three different subscription packages for its customers: Package A: For $9.95 per month 10 hours of access are provided. Additional hours are $2.00 per hour. Package B: For $14.95 per month 20 hours of access are provided. Additional hours are $1.00 per hour. Package C: For $19.95 per month unlimited access is provided. Write a program that calculates a customer's monthly bill. It should ask which package the customer has purchased and how many hours were used. It should then display the total amount due. Input Validation: Be sure the user only selects package A, B or C. Also, the number of hours used in a month cannot exceed 744. Use switch.

In C++:

#include <iostream>

using namespace std;

int main(){

   int hour; char pkg; float bill = 0;

   cout<<"Package: "; cin>>pkg;

   cout<<"Hour: "; cin>>hour;

   if(hour<=744 && hour >=0){

       switch (pkg) {

           case 'A':

               bill = hour * 9.95;

               if(hour >10){bill = 10 * 9.95 + (hour - 10) * 2;}

           break;

           case 'B':

               bill = hour * 14.5;

               if(hour >10){bill = 20 * 14.5 + (hour - 20) * 1;}

           break;

           case 'C':

               bill = 19.95;

           break;

           default:

               cout << "Package must be A, B or C";}

cout<<"Total Bills: $"<<bill; }

else{ cout<<"Hour must be 0 - 744"; }

return 0;

}

Explanation:

This declares all variables:    int hour; char pkg; float bill=0;

This prompts the user for package type:  cout<<"Package: "; cin>>pkg;

This prompts the user for number of hours:    cout<<"Hour: "; cin>>hour;

This checks if hour is between 0 and 744 (inclusive)

   if(hour<=744 && hour >=0){

If true, the following is executed

A switch statement to check valid input for package

       switch (pkg) {

For 'A' package

           case 'A':

Calculate the bill

               bill = hour * 9.95;

               if(hour >10){bill = 10 * 9.95 + (hour - 10) * 2;}

End of A package:            break;

For 'B' package

           case 'B':

Calculate the bill

               bill = hour * 14.5;

               if(hour >10){bill = 20 * 14.5 + (hour - 20) * 1;}

End of B package:            break;

For C package            

           case 'C':

Calculate bill:                bill = 19.95;

End of C package:            break;

If package is not A, or B or C

           default:

Prompt the user for valid package                cout << "Package must be A, B or C";}

Print total bills: cout<<"Total Bills: $"<<bill; }

If hour is not 0 to 744: else{ cout<<"Hour must be 0 - 744"; }