Arduino program 1 push button 2 LED

[docdoc]

@paulpaulson

enum LedNames {Red,Green};
constexpr uint8_t LedPins[] {9,10};  // [port pin] --  -->|--  -- [GND]
constexpr uint8_t ButtonPin {A0};    // [port pin] -- [button] -- [GND]

Thank you, I learned something new to me, I didn't know "constexpr" so I'd neve thought using "constexpr" to do that!

By the way, I understand the first "constexpr" is useful when defining constant arrays, but how the second one differs from a standard "const uint8_t ButtonPin = A0;"?