Compile Time Constant¶

A compile time constant (CTC) is a value that can be computed at compile time. There are three types of compile time constants.

literals
static constants which are initialized with a literal
induction variables

There are four cases where only compile time constants are allowed.

loop bound
array size
size in reverseBytes(bytes b, int size)
size in repeat(T e, int size)

contract CTC {
    static const int N = 4;
    static const int LOOPCOUNT = 30;

    // A is not a CTC because the right hand size is an expression, not a literal
    static const int A = 2 + 1;
    // B is not a CTC because it is not static
    const int B = 2;

    public function unlock(int y) {
        int[N] arr = [1, 2, 3, 4];

        int z = 0;
        loop (LOOPCOUNT)
        {
            if (z<y) z += 4;
        }
        require(y == 1);
    }
}