I would like to ask you what’s the most efficient way for checking user’s input in C. I want the user to enter a 4 digit integer. How can I make sure that the user has entered exactly 4 digits and no letters?
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I would like to ask you what’s the most efficient way for checking user’s input in C. I want the user to enter a 4 digit integer. How can I make sure that the user has entered exactly 4 digits and no letters?
One way:
1) read as
stringorchar*2) check each char falls within 49-58 ASCII range.
Finally, convert into
intusingatoi()(or atol() in case of long) if there are only four chars in the string and satisfy (2)