L E S S O N S E T 5 Loops and Files LAB 5.2 Working with the do-while Loop Bring in the program dowhile.cpp from the Lab 5 folder. The code is shown below: // This program displays a hot beverage menu and prompts the user to // make a selection. A switch statement determines which item the user // has chosen. A do-while loop repeats until the user selects item E // from the menu. // PLACE YOUR NAME HERE #include #include using namespace std; int main() { // Fill in the code to define an integer variable called number, // a floating point variable called cost, // and a character variable called beverage bool validBeverage; cout << fixed << showpoint << setprecision(2); do { cout << endl << endl; cout << "Hot Beverage Menu" << endl << endl; cout << "A: Coffee $1.00" << endl; cout << "B: Tea $ .75" << endl; cout << "C: Hot Chocolate $1.25" << endl; cout << "D: Cappuccino $2.50" << endl << endl << endl; continues 68 LESSON SET 5 Loops and Files cout << "Enter the beverage A,B,C, or D you desire" << endl; cout << "Enter E to exit the program" << endl << endl; // Fill in the code to read in beverage switch(beverage) { case 'a': case 'A': case 'b': case 'B': case 'c': case 'C': case 'd': case 'D': validBeverage = true; break; default: validBeverage = false; } if (validBeverage == true) { cout << "How many cups would you like?" << endl; // Fill in the code to read in number } // Fill in the code to begin a switch statement // that is controlled by beverage { case 'a': case 'A': cost = number * 1.0; cout << "The total cost is $ " << cost << endl; break; // Fill in the code to give the case for hot chocolate ($1.25 a cup) // Fill in the code to give the case for tea ( $0.75 a cup) // Fill in the code to give the case for cappuccino ($2.50 a cup) case 'e': case 'E': cout << " Please come again" << endl; break; default:cout << // Fill in the code to write a message // indicating an invalid selection. cout << " Try again please" << endl; } } // Fill in the code to finish the do-while statement with the // condition that beverage does not equal E or e. // Fill in the appropriate return statement } Lesson 5A 69 L E S S O N 5 B Exercise 1: Fill in the indicated code to complete the above program. Then compile and run the program several times with various inputs. Try all the possible relevant cases and record your results. Exercise 2: What do you think will happen if you do not enter A, B, C, D or E? Try running the program and inputting another letter. Exercise 3: Replace the line if (validBeverage == true) with the line if (validBeverage) and run the program again. Are there any differences in the execution of the program? Why or why not?
L E S S O N S E T
5 Loops and Files
LAB 5.2 Working with the do-while Loop
Bring in the
below:
// This program displays a hot beverage menu and prompts the user to
// make a selection. A switch statement determines which item the user
// has chosen. A do-while loop repeats until the user selects item E
// from the menu.
// PLACE YOUR NAME HERE
#include <iostream>
#include <iomanip>
using namespace std;
int main()
{
// Fill in the code to define an integer variable called number,
// a floating point variable called cost,
// and a character variable called beverage
bool validBeverage;
cout << fixed << showpoint << setprecision(2);
do
{
cout << endl << endl;
cout << "Hot Beverage Menu" << endl << endl;
cout << "A: Coffee $1.00" << endl;
cout << "B: Tea $ .75" << endl;
cout << "C: Hot Chocolate $1.25" << endl;
cout << "D: Cappuccino $2.50" << endl << endl << endl;
continues
68 LESSON SET 5 Loops and Files
cout << "Enter the beverage A,B,C, or D you desire" << endl;
cout << "Enter E to exit the program" << endl << endl;
// Fill in the code to read in beverage
switch(beverage)
{
case 'a':
case 'A':
case 'b':
case 'B':
case 'c':
case 'C':
case 'd':
case 'D': validBeverage = true;
break;
default: validBeverage = false;
}
if (validBeverage == true)
{
cout << "How many cups would you like?" << endl;
// Fill in the code to read in number
}
// Fill in the code to begin a switch statement
// that is controlled by beverage
{
case 'a':
case 'A': cost = number * 1.0;
cout << "The total cost is $ " << cost << endl;
break;
// Fill in the code to give the case for hot chocolate ($1.25 a cup)
// Fill in the code to give the case for tea ( $0.75 a cup)
// Fill in the code to give the case for cappuccino ($2.50 a cup)
case 'e':
case 'E': cout << " Please come again" << endl;
break;
default:cout << // Fill in the code to write a message
// indicating an invalid selection.
cout << " Try again please" << endl;
}
} // Fill in the code to finish the do-while statement with the
// condition that beverage does not equal E or e.
// Fill in the appropriate return statement
}
Lesson 5A 69
L E S S O N 5 B
Exercise 1: Fill in the indicated code to complete the above program. Then
compile and run the program several times with various inputs. Try all the
possible relevant cases and record your results.
Exercise 2: What do you think will happen if you do not enter A, B, C, D
or E? Try running the program and inputting another letter.
Exercise 3: Replace the line
if (validBeverage == true)
with the line
if (validBeverage)
and run the program again. Are there any differences in the execution of
the program? Why or why not?
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