What does this line mean? What for "out size"? The rest is clear)

Question

(! int. TryParse(Console. ReadLine(), out size) || size<1)

Answer 1

out is used to pass variables by reference (so when the method is done, the variables are still changed).

TryParse returns two values. It returns a boolean, for if the parse worked or not. If the parse does work, it also returns the value it just converted (and stores it in the 'out' variable).

Answer 2

size is the name of the variable where the return value from out is stored.