Let's say you are asking for a 3-digit security code; not only do we need to check for an integer, but an integer whose length is 3 digits.The following code makes sure that the user enters a 3-digit number.Is there a way to recognise that strings like 123xyz is an invalid input and to disregard the whole input? Its from cctype library, and is sometimes automatically included when compiling CPP, so you don't need to #include the cctype library.Therefore, if you have to enter a 25-character code, you would make the array having 26 indices.For user validation, the program should make use of a loop so that users have an opportunity to enter the correct data.Data can be entered incorrectly either by mistake or on purpose.C programmers must be vigilant to ensure both malicious and unintentional bad entry does not occur.
This is actually an infinite loop, but it is only broken if the user actually enters the right length of security code! Many times we need to ask for text or character data from the user.
We need to add the statement to import it, before any other functions (main or otherwise).
We already used scanf (in the code above) to read user input.
The program might crash, but that is a consequence of GIGO. It accepts a single character from the user: Go ahead and copy this into your compiler; compile and run.
You can enter a 7, or a 3 or even an entire string of text.