Why does sizeof(!5.6) give an output 2?

Question

Even if we declare float a=5.6 then printf("%d",sizeof(!a)) outputs 2. Why does it output size of integer?

Answer 1

The ! operator returns an integral type, likely int. sizeof(int) == 2 on your architecture, apparently.

Answer 2

The ! operator doesn't return the type of the operand. If you perform a NOT on a float, you're not going to get a float back. You are going to get an int with the logically opposite value of the initial float.