char quitKey = 'y';
do
    {
        cout << quitKey;
    }
    while (quitKey != 'y');

I kept getting an error because instead of endl (lowercase L) I put end1 (ONE). I think you should put this up there since even though it’s humiliating I took a “little” while trying to fix it (thanks to Google..) someone else might encounter the same thing I did.

[ That's a great point. I'll add it to the FAQ. I added some additional advice in the answer to this issue. -Alex ]

#include <iostream>

int main()
{
    using namespace std;

    // Allocate a buffer to hold user input
    char buf[255] = { 0 };

    // We only want one letter
    cout << "Enter a letter: ";
    cin >> buf[0];

    // Pause and wait for user input
    char chIgnore;
    cout << "Pausing" << endl;
    cin >> chIgnore;

  return 0;
}

First, cin >> chIgnore ignores the enter key if the user does not provide any other input. You can verify this by hitting enter when the cin >> chIgnore line is being executed. On the other hand, cin.get() accepts the enter key as valid input.

But perhaps more importantly is the second phenomena that occurs when more characters are placed into the input stream (cin) than are read out. When asked for a letter in the above program, enter more than one letter and watch what happens.

Let’s say you enter “abcde”. cin >> buf[0] reads the ‘a’ character, but “bcde” are still left in the input stream. Consequently, when the code gets to cin >> chIgnore, it reads the waiting ‘b’ character out of the input stream and doesn’t pause at all!

The 3 step process is a little more foolproof. First, cin.clear() clears any errors the user may have caused by providing invalid input in the past. Second, cin.ignore(255, 'n') gets rid of up to 255 waiting characters in the input stream (or until a n is encountered), which is almost always going to be enough to clear out the input stream. Finally, we use cin.get() to wait for a character. Since we just cleared the input stream, there are no characters waiting. Consequently, the program will wait for the user to enter something.

In 99% of the cases you encounter, cin >> myVariable will probably work exactly as you expect. But since the 3 line method is generally more foolproof and isn’t particularly burdensome to implement, I’d say it’s the superior solution.

cin.clear();
cin.ignore(255, '\n');
cin.get();

have any advantages over just using

cin >> myVariable;

I have so much to learn. :)

The ide I’m using is Visual C .NET 2002. This ide has problem 1.

To fix the problem I include the following command at the end of the main() function before the return statement.

system(”pause”);

[ Unfortunately, this only works on the Windows operating system. The system() function tells the operating system to execute whatever the parameter is -- in this case, a command named "pause". On Windows, this waits for user input. On other operating systems (such as linux), the pause command does something else entirely. However, if you are only programming on Windows and not distributing your source code, you may find this an easier solution while learning. -Alex ]