[DaWei]

How can you say you're sticking with C when you're using C++ streams? Everyone is entitled to their opinion, of course, but your remarks have no real technical validity. C++ will almost always result in more robust code with fewer errors, with little, if any, performance degradation. It represents a mature advance made possible by technological gains.

Here are versions for C and C++.

C++

#include <iostream>

using std::cin;
using std::cout;
using std::endl;

int menu ();

int main ()
{
	int choice = 0;
	while (choice != 3)
	{
		choice = menu ();
		cout << "Your choice was " << choice << endl;
	}
	return 0;
}

int menu ()
{
	int choice = 0;
	while (1)
	{
		cout << "Enter your selection (1, 2, 3 to exit): ";
		cin >> choice;
		if (!cin.good ()) choice = 0;
		if ((choice < 1) || (choice > 3))
			cout << "Your selection was invalid.  Try again.\n" << endl;
		else return choice;
		cin.sync ();
		cin.clear ();
	}
	return choice;
}

C

#include <stdio.h>

int menu ();

int main (int argc, char *argv [])
{
	int choice = 0;
	while (choice != 3)
	{
		choice = menu ();
		printf ("Your choice was %d\n", choice);
	}
	return 0;
}
int menu ()
{
	int choice = 0;
	while (1)
	{
		printf ("Enter your selection (1, 2, 3 to exit): ");
		if (scanf ("%d", &choice) != 1) choice = 0;
		if ((choice < 1) || (choice > 3))
			puts ("Your selection was invalid.  Try again.\n\n");
		else return choice;
		rewind (stdin);
	}
	return choice;
}

Quote:

Originally Posted by Output

E:\Documents and Settings\David\My Documents\Visual Studio 2005\Projects\Menu\de
bug>menu
Enter your selection (1, 2, 3 to exit): aaa
Your selection was invalid. Try again.

Enter your selection (1, 2, 3 to exit): bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
Your selection was invalid. Try again.

Enter your selection (1, 2, 3 to exit): 33
Your selection was invalid. Try again.

Enter your selection (1, 2, 3 to exit): 1
Your choice was 1
Enter your selection (1, 2, 3 to exit): 2
Your choice was 2
Enter your selection (1, 2, 3 to exit): 3
Your choice was 3

E:\Documents and Settings\David\My Documents\Visual Studio 2005\Projects\Menu\de
bug>