Help with using a Class functionality within another functionality

Each functionality of the class should do only one thing. So I am trying to get the stuff from the functionality get_monthly_total inside the functionality of show_info. However, I have been unsuccessful at all of my attempts. I just don't know the syntax to accomplish this. Can someone please provide a suggestion? Thanks.

Code:

# include <iostream>
# include <string>
# include <cstdlib>
using namespace std ;


class Standard_Plan
{
      public :
             void input_hours_online () ;
             void show_info () ;
             double get_monthly_total () ;
      
      private :
              double the_hours_online ;
              
} ;


class Premium_Plan
{
      public :
             void input_hours_online () ;
             void show_info () ;
             double get_monthly_total () ;
      
      private :
              double the_hours_online ;
              
} ;
              


int main ()
{
    cout << "This will Calculate your Monthly Bill." <<endl ;
    
    
    // This will determine whether user is in Standard Plan or Premium Plan.
    
    char response ;
    cout << "Are you Subscribed to the Standard or Premium Plan? Enter s or     
p: " ;
    cin >> response ;
    
    if (response == 's')
    {
      Standard_Plan  aStandardPlan ;
      aStandardPlan . input_hours_online () ;
      aStandardPlan . show_info () ;          
    }
    
    else
         {
           Premium_Plan  aPremiumPlan ;
           aPremiumPlan . input_hours_online () ;
           aPremiumPlan . show_info () ; 
         }

     
    system("PAUSE") ;

    return 0 ;
}




 void Standard_Plan :: input_hours_online () 
 {
      cout << "Enter Number of Hours Used: " ;
      cin >> the_hours_online ;
      cout << "You are Subscribed to the Standard Plan" ;      
 }


 void Premium_Plan :: input_hours_online () 
 {
      cout << "Enter Number of Hours Used: " ;
      cin >> the_hours_online ;
 }
 
void Standard_Plan :: show_info () 
 {
   cout << get_monthly_total () ;                  
 }

void Premium_Plan :: show_info () 
 {
  cout << get_monthly_total () ;    
 }

double get_monthly_total ()
{
      double base_charge ;
      double additional_charge ;
      double premium_discount ;
      char response ;
      int the_hours_online ;
      
      if (response == 's')
       {
                   // This will calculate charges for Standard Plan
                 
                 if (the_hours_online <= 20)
                 {
                     base_charge = 20.00 ;
                     cout << "Fixed Monthly Charge is: $" << base_charge << endl ;
                     cout << "Total Monthly Bill is: $" << base_charge << endl ;
                 }
                                                        
                 if (the_hours_online > 20)
                 {
                     base_charge = 20.00 ;
                     additional_charge = (the_hours_online - 20) * 00.50 ;
                     cout << "Fixed Monthly Charge is: $" << base_charge << endl ;
                     cout << "Additional Charges: $" << additional_charge << endl ;
                     cout << "Total Monthly Bill is: $" << base_charge + additional_charge << endl ;
                 } 
       }
       
      else
       
       {
       // This will calculate charges for Premium Plan
                 
                 if (the_hours_online <= 30)
                 {
                     base_charge = 25.00 ;
                     additional_charge = 0.00 ;
                     premium_discount = (base_charge + additional_charge) * .10 ;
                     cout << "Fixed Monthly Charge is: $" << base_charge << endl ;
                     cout << "10% Discount off Bill: $" << premium_discount << endl ;
                     cout << "Total Monthly Bill is: $" << base_charge - premium_discount << endl ;
                 }
                  
         
                 if (the_hours_online > 30)
                 {
                     base_charge = 25.00 ;
                     additional_charge = (the_hours_online - 30) * 00.50 ;
                     premium_discount = (base_charge + additional_charge) * .10 ;
                     cout << "Fixed Monthly Charge is: $" << base_charge << endl ;
                     cout << "Additional Charges: $" << additional_charge << endl ;
                     cout << "10% Discount off Bill: $" << premium_discount << endl ;
                     cout << "Total Monthly Bill is: $" << (base_charge + additional_charge) - premium_discount << endl ;
                 }

       }
}

You really don't need so many newlines at the end of your program . . . .

Code:

double get_monthly_total ()

Is that supposed to be prefixed with a class?

> However, I have been unsuccessful at all of my attempts.
Start by reading about inheritance

You have a plan (stuff common to all plans)

From that, you derive two specialised plans called 'standard' and 'premium'.

For example, your input_hours_online() is essentially the same code for both, so it would be in the plan base class. Doing this, you would only have to write the code once, not copy/paste it.

Originally Posted by Salem

> However, I have been unsuccessful at all of my attempts.
Start by reading about inheritance

For example, your input_hours_online() is essentially the same code for both, so it would be in the plan base class. Doing this, you would only have to write the code once, not copy/paste it.

The assignment mentioned that we would be doing inheritance at the end of the semester. So for now, we are only supposed to use standard classes.


[QUOTE]
You really don't need so many newlines at the end of your program . . . .
[QUOTE]

I have a tendency to do this. After everyting is working I go back and format things correctly with respect to new lines.

Code:
double get_monthly_total ()Is that supposed to be prefixed with a class?

double get_monthly_total () is a functionality of both classes. I was wondering if it was possible to use that functionality within the show_info () functionality of the classes. Something like:

Code:

void Standard_Plan :: show_info () 
 {
   cout << get_monthly_total () ;                  
 }

void Premium_Plan :: show_info () 
 {
  cout << get_monthly_total () ;    
 }

so that in the main block, apremiumplan . show_info () for example, would output the calculations and stuff from get_monthly_total () .

Yes, you can call a common function from two different class member functions.

Originally Posted by Salem

Yes, you can call a common function from two different class member functions.

This does not work.

Code:

void Standard_Plan :: show_info () 
 {
   cout << get_monthly_total () ;                  
 }

void Premium_Plan :: show_info () 
 {
  cout << get_monthly_total () ;    
 }

I have tried just about everything, but no success. Can you tell me what the general syntax is so this way I can fix the program? Thanks.

You didn't remove the member functions with the same name

Code:

# include <iostream>
# include <string>
# include <cstdlib>
using namespace std;

//!! A common function, not in any class
double get_monthly_total();

class Standard_Plan {
  public:
    void input_hours_online();
    void show_info();
    //!! double get_monthly_total () ;

  private:
    double the_hours_online;

};


class Premium_Plan {
  public:
    void input_hours_online();
    void show_info();
    //!! double get_monthly_total () ;

  private:
    double the_hours_online;

};



int main()
{
    cout << "This will Calculate your Monthly Bill." << endl;

    // This will determine whether user is in Standard Plan or Premium Plan.
    char response;
    cout <<
        "Are you Subscribed to the Standard or Premium Plan? Enter s or p: ";
    cin >> response;

    if (response == 's') {
        Standard_Plan aStandardPlan;
        aStandardPlan.input_hours_online();
        aStandardPlan.show_info();
    } else {
        Premium_Plan aPremiumPlan;
        aPremiumPlan.input_hours_online();
        aPremiumPlan.show_info();
    }


    system("PAUSE");

    return 0;
}




void Standard_Plan::input_hours_online()
{
    cout << "Enter Number of Hours Used: ";
    cin >> the_hours_online;
    cout << "You are Subscribed to the Standard Plan";
}


void Premium_Plan::input_hours_online()
{
    cout << "Enter Number of Hours Used: ";
    cin >> the_hours_online;
}

void Standard_Plan::show_info()
{
    cout << get_monthly_total();
}

void Premium_Plan::show_info()
{
    cout << get_monthly_total();
}

double get_monthly_total()
{
    double base_charge;
    double additional_charge;
    double premium_discount;
    char response;
    int the_hours_online;

    if (response == 's') {
        // This will calculate charges for Standard Plan

        if (the_hours_online <= 20) {
            base_charge = 20.00;
            cout << "Fixed Monthly Charge is: $" << base_charge << endl;
            cout << "Total Monthly Bill is: $" << base_charge << endl;
        }

        if (the_hours_online > 20) {
            base_charge = 20.00;
            additional_charge = (the_hours_online - 20) * 00.50;
            cout << "Fixed Monthly Charge is: $" << base_charge << endl;
            cout << "Additional Charges: $" << additional_charge << endl;
            cout << "Total Monthly Bill is: $" << base_charge +
                additional_charge << endl;
        }
    }

    else
    {
        // This will calculate charges for Premium Plan

        if (the_hours_online <= 30) {
            base_charge = 25.00;
            additional_charge = 0.00;
            premium_discount = (base_charge + additional_charge) * .10;
            cout << "Fixed Monthly Charge is: $" << base_charge << endl;
            cout << "10% Discount off Bill: $" << premium_discount << endl;
            cout << "Total Monthly Bill is: $" << base_charge -
                premium_discount << endl;
        }


        if (the_hours_online > 30) {
            base_charge = 25.00;
            additional_charge = (the_hours_online - 30) * 00.50;
            premium_discount = (base_charge + additional_charge) * .10;
            cout << "Fixed Monthly Charge is: $" << base_charge << endl;
            cout << "Additional Charges: $" << additional_charge << endl;
            cout << "10% Discount off Bill: $" << premium_discount << endl;
            cout << "Total Monthly Bill is: $" << (base_charge +
                                                   additional_charge) -
                premium_discount << endl;
        }

    }
    //!! MUST return a result
    return base_charge + additional_charge;
}

Study the //!! comments

Thanks for your help!