%s is a string format specification. The format specification matches /%([+-0#]? \d+ (.\d+)) ([bcdefginopsuxDEFGOUX])/x. Possibly most interesting to you are that a - left justifies in a field. The first digit group specifies the field width (minimum width for strings) and the second digit group is decimal digits for floats, minimum field width for integers and maximum field width for strings.

The flags most likely of interest to you are 'd' or 'i' (integer), 'f' (float) and 's' (string).

ya the only problem is if you port it to C it isnt going to function as it requires an integer type.long long type to be specific, but it isnt working on my system so hence the perl