Visual C++ and MFC Programming 2nd Edition

Chapter 20: List-Based Controls Visual C++ and MFC Fundamentals

8. Implement the method as follows:

void CFastFoodDlg::EvaluatePrice(void)

{

double PriceBread, PriceMeat,

PriceCheese, PriceBacon, TotalPrice;

// The price of bread is $0.85

PriceBread = 0.85;

// To get the price of the meat, find out what button

// is selected in the Meat group box

switch(GetCheckedRadioButton(IDC_MEAT, IDC_CHICKEN_BREAST))

{

case IDC_MEAT:

// The beef patty is $1.50

PriceMeat = 1.50;

break;

case IDC_GRILLED_CHICKEN:

case IDC_CHICKEN_BREAST:

// Cheicken breast and grilled chicken are $1.80 each

PriceMeat = 1.80;

break;

default: // Why are we adding this?

PriceMeat = 0.00;

}

// There is no extra cost for the Regular ingredients

// and nothing to add for the sweetener

// On the other hand,

// if the customer wants cheese, $0.30 is added to the price

if( IsDlgButtonChecked(IDC_CHK_CHEESE) == 1 )

PriceCheese = 0.30;

else // otherwise, the customer don't want no cheese

PriceCheese = 0.00;

// If the customer wants bacon, $0.45 is added to the price

if( IsDlgButtonChecked(IDC_CHK_BACON) == 1 )

PriceBacon = 0.45;

else

PriceBacon = 0.00;

// Now, we can calculte the total price

TotalPrice = PriceBread + PriceMeat + PriceCheese + PriceBacon;

// Convert the price to a null-terminated string

char StrTotalPrice[10];

sprintf(StrTotalPrice, "$%.2f", TotalPrice);

// Display the price

m_TotalPrice.SetWindowText(StrTotalPrice);

}

9. To update the price and its display live whenever the user makes a new selection,
   generate a BN_CLICKED message for the IDC_MEAT, the
   IDC_GRILLED_CHICKEN, the IDC_CHICKEN_BREAST, the
   IDC_CHK_CHEESE, and the IDC_CHK_BACON check boxes


10. In the body of each, simply call the above EvaluatePrice() method. Here are two
    examples to save printing paper:

void CFastFoodDlg::OnBnClickedGrilledChicken()