Initializing constant variable based on constexpr condition

Question

How can I initialize constant variable based on constexpr condition?

I need initialization equivalent to this non-compilable code:

const int x;
if constexpr(cond)
    x = value1; // value1 may not be valid if cond is false
else        
    x = value2; // value2 may not be valid if cond is true

Answer 1

constexpr int x = []{
    if constexpr (cond)
        return value1;
    else        
        return value2;
}();