Question

Simple question. In my code I set a double to an integer, like so:

int square_root = sqrt(sum);

Do I need to explicitly cast this?

Without casting, I seem to get the result I desired, i.e. floor(sqrt(x))

sqrt(4200) = 64
sqrt(42) = 6

Answer 1

 int square_root = sqrt(sum);

is equivalent in C to:

int square_root = (int) sqrt(sum);

Now be aware that if the integral part of a double is not representable in an int the behavior is undefined (in both cases).