Done.

Added static and random tests.

Done.

I see now. This is pretty strange. Maybe Codewars bug?

Bug is in this line:

printLn (bar [1])

bar is partial function, which means it does not handle all possible inputs. It does handle only []. You pass [1] to it and get runtime crash.

Why not

int manhattan_distance(int x1, int x2, int y1, int y2);

?

C translation is ready! Please review and approve.

Function should take one number.

Cool!

There are no random test cases

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I could not understand how.

Done.

Fixed.