Newbie question (user error checking)

I'm just starting to learn C++.. and this is really my first programming language, but I'm not sure how to prevent users from messing up my program when they start entering garbage. Here's an example I wrote:

Code:

---

#include <iostream>
using namespace std;

int main() {
        int choice;
        while (choice != 3) {
                cout << "Choice: ";
                cout << "\n(1) First\n(2) Second\n(3) Quit\n\n";
                cin >> choice;
                if (choice == 1) {
                        cout << "First\n";
                }
                if (choice == 2) {
                        cout << "Second\n";
                }
        }
        cout << "Exit\n";
        return 0;
}

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Now lets say someone enters 'g'... it would just go into an infinite while loop.. and I'd have to close it. I've actually had this problem for quite a while. Any help is really appreciated :)

See: http://www.parashift.com/c++-faq-lit....html#faq-15.2

You can test cin for failure and act accordingly:

Code:

---

#include <iostream>
using namespace std;

int main() {
        int choice;
        while (choice != 3) {
                cout << "Choice: ";
                cout << "\n(1) First\n(2) Second\n(3) Quit\n\n";
               
    cin >> choice;
    if ( !cin )
      break;

                if (choice == 1) {
                        cout << "First\n";
                }
                if (choice == 2) {
                        cout << "Second\n";
                }
        }
        cout << "Exit\n";
        return 0;
}

---

-Prelude

try this..

Code:

---

#include <iostream>
using namespace std;

int main() {
        char choice;
        while (choice != '3') {
                cout << "Choice: ";
                cout << "\n(1) First\n(2) Second\n(3) Quit\n\n";
                cin >> choice;
                if (choice == '1') {
                        cout << "First\n";
                }
                if (choice == '2') {
                        cout << "Second\n";
                }
        }
        cout << "Exit\n";
        return 0;
}

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The problem was that it only accepted numbers. Now it should work...

Wow what a quick response! Thanks so much guys

I didn't realize you could do that with cin :D

Quote:

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The problem was that it only accepted numbers. Now it should work...

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Wouldn't it still screw up if the user typed in "asdfgjskdfjsf"?

Quote:

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Originally posted by Hunter2
Wouldn't it still screw up if the user typed in "asdfgjskdfjsf"?

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Or if choice was initially '3', which you have no control over seeing as it's uninitilized.