4elist0717.cpp

《21天学通C＋＋》附盘的原代码。书上的每个例子在这里都有相应的C语言程序。

//Listing 7.17
//Using a forever loop to manage
//user interaction
#include <iostream>

// prototypes
int menu();
void DoTaskOne();
void DoTaskMany(int);

using namespace std;

int main()
{
	bool exit = false;
	for (;;)
	{
		int choice = menu();
		switch(choice)
		{
		case (1):
			DoTaskOne();
			break;
		case (2):
			DoTaskMany(2);
			break;
		case (3):
			DoTaskMany(3);
			break;
		case (4):
			continue;  // redundant!
			break;
		case (5):
			exit=true;
			break;
		default:
			cout << "Please select again!\n";
			break;
		}          // end switch

		if (exit)
			break;
	}                // end forever
	return 0;
}                    // end main()

int menu()
{
	int choice;

	cout << " **** Menu ****\n\n";
	cout << "(1) Choice one.\n";
	cout << "(2) Choice two.\n";
	cout << "(3) Choice three.\n";
	cout << "(4) Redisplay menu.\n";
	cout << "(5) Quit.\n\n";
	cout << ": ";
	cin >> choice;
	return choice;
}

void DoTaskOne()
{
	cout << "Task One!\n";
}

void DoTaskMany(int which)
{
	if (which == 2)
		cout << "Task Two!\n";
	else
		cout << "Task Three!\n";
}