C++ Book


Introducing the Menu Chooser Program

ScreenShot

The Menu Choose Program presents the user with a menu that lists three difficulty levels and asks him to make a choice. If the user enters a number that corresponds to a listed choice, then he is shown message confirming the choice. If the the user makes some other choice, he is told that choice is invalid.

Creating Multiple Ways to Branch

The switch statement creates four possible branching points. If the user enters 1, then code associated with case 1 is execured and “You picked Easy” is displayed. If the user enters 2, then code associated with case 2 is executed and “You picked Normal: is displayed. If the user enters 3, then code associated with case 3 is executed and “You picked Hard” is displayed. If the user enters any other value, then default kicks in and “You made an illegal choice” is displayed.

Trap

You’ll almost always want to end each case with a break statement. Don’t forget them; otherwise, your code might do things you never intended.

Using While Loops

while loops let you repeat sections of code as long as an expression is true. Here’s a generic form of the while loop:

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while (expression)
    statement;

If expression is false, the program moves on to the statement after the loop. If expression is true, the program executes statment and loops back to test expression again. This cycle repeats until expression test false, at which point the loop ends.

Code

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// Menu Chooser
// Demostartes the switch statement

#include <iostream>

using namespace std;

int main() {
	cout << "Difficulty Levels\n\n";
	cout << "1 - Easy\n";
	cout << "2 - Normal\n";
	cout << "3 - Hard\n\n";

	int choice;
	cout << "Choice: ";
	cin >> choice;

	switch (choice) {
	case 1: 
		cout << "You picked Easy. \n";
		break;

	case 2: 
		cout << "You picked Normal.\n";
		break;

	case 3: 
		cout << "You picked Hard.\n";
		break;

	default:
		cout << "You made an illegal choice.\n";
	}

	return 0;
}

Output

Easy

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Difficulty Levels

1 - Easy
2 - Normal
3 - Hard

Choice: 1
You picked Easy.

Normal

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8

Difficulty Levels

1 - Easy
2 - Normal
3 - Hard

Choice: 2
You picked Normal.

Hard

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Difficulty Levels

1 - Easy
2 - Normal
3 - Hard

Choice: 3
You picked Hard.