How to Handle Incorrect Data Type Input and Avoid Infinite Loops in C ?

Handling Incorrect Data Type Input in C

In C , incorrect data type input can lead to infinite loops when the program fails to process input of the expected type. For instance, if an integer is requested but a character is entered, the program may enter an endless input loop.

Solution:

The underlying issue is the setting of the "bad input flag" in std::cin when input does not adhere to the expected type. To address this:

1. Clear the Bad Input Flag: Utilize std::cin.clear() to reset the flag, indicating that the input is now acceptable.
2. Discard Bad Input: Employ std::cin.ignore() to remove incorrect input from the input buffer.

The following code snippet demonstrates this solution:

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 loop continues until valid input is provided.

Alternatively, one can obtain input as a string and convert it to an integer using std::stoi or similar methods that enable conversion validation.

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