How this function works?

Question

int is_digit(char c) {
return ('0' <= c) && (c <= '9');
}

Answer 1

Chars are basically just integers, which under certain circumstances get interpreted like characters.
'0' is 48, '9' is 57. If the input char is between 48 and 57, it's a digit.

Answer 2

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Answer 3

Martin Taylor , I'm a beginner and learning C language. That's why I'm trying to build this function. Thank you.