1. int a = int();
    default value is assigned - 0
2. int c = sizeof(++a);
    The sizeof operator yields the number of bytes in the object representation of its operand. The operand is either an expression, which is not evaluated, or a parenthesized type-id ... The expression of the operand is not evaluated. Therefore, the increment operation will not be performed
3. c = a++;
the assignment is performed first and then the increment operation