Question

OK so I tried doing this

 int b;
 char x = 'a';

//Case 1    
b = static_cast<int>(x); 
std::cout<<"B is : "<<b<<std::endl;

//Case 2
b = *(int*)&x;   
std::cout<<"B is changed as  :: "<< b <<std::endl;

Now I know that in case 2, first byte of x is reinterpreted to think that it is an integer and the bit pattern is copied into b which gives of some garbage and in case 1 it just converts the value from char to int.

Apart from that are there any differences between these two?

Answer 1

The first one just converts the value: int b = x; is the same as int b = static_cast<int>(x);.

The second case pretends that there is an int living at the place where in actual fact the x lives, and then tries to read that int. That’s outright undefined behaviour. (For example, an int might occupy more space than a char, or it might be that the char lives at an address where no int can ever live.)