can we declare enum in main function in c++ code example

Example 1: enum c++

enum Colors
{
        BLACK,
        GREEN,
        BLUE,
        RED
};

Example 2: enum c++

enum Foo { a, b, c = 10, d, e = 1, f, g = f + c };
//a = 0, b = 1, c = 10, d = 11, e = 1, f = 2, g = 12