How Can I Gracefully Handle Invalid Input in C ?

Addressing Invalid Input in C

In C , input validation is crucial to handle unexpected or incorrect user input. This ensures that your program can handle diverse input scenarios and avoids potential errors.

Consider a situation where your program requests an integer but receives a character instead. To prevent an infinite loop caused by this mismatch, it's important to clear the bad input flag set by std::cin and discard the invalid input.

// Clear bad input flag and discard invalid input
while (std::cout << "Enter a number" && !(std::cin >> num)) {
    std::cin.clear(); // Clear bad input flag
    std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); // Discard input
    std::cout << "Invalid input; please re-enter.\n";
}

This code snippet checks if the input operation fails, then clears the bad input flag using std::cin.clear() and discards the invalid input with std::cin.ignore(). By looping until valid input is received, your program can prevent infinite loops and handle invalid input gracefully.

Alternatively, you can capture the input as a string and convert it to an integer using std::stoi or another method that allows for conversion validation. This approach provides flexibility in handling a range of input scenarios.

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