What is the effect of trailing white space in a scanf() format string?

Question

What is difference between scanf(\"%d\") and scanf(\"%d \") in this code, where the difference is the trailing blank in the format string?

Answer 1

A whitespace character in your scanf format matches any number of whitespace characters as described by isspace. So if you have tailing spaces, newlines, tabulators or any other whitespace character then it will also be consumed by scanf before it returns.