Undefined behaviour of const

Question

I never thought I will be going to ask this question but I have no idea why this happens.

const int a = 3; 
int *ptr;
ptr = (int*)( &a );
printf( \"A=%d\         


        

Answer 1

The optimizer can determine that a is a constant value, and replace any reference to it with the literal 3. That explains what you see, although there's no guarantee that's what's actually happening. You'd need to study the generated assembly output for that.