C++ Undefined behaviour with unions

Question

Was just reading about some anonymous structures and how it is isn\'t standard and some general use case for it is undefined behaviour...

This is the basic case:

Answer 1

I did not get why you have used float v[2];

The simple union for a point structure can be defined as:

union{

struct {

    float a;
    float b;
};

} Point;

You can access the values in unioin as:

Point.a = 10.5; 

point.b = 12.2; //example