Why the following code is printing b =5 instead of b =4 as it decremented after the operation?

Question

after the operation, b should equal to 5, then be should post decrement resulting b = 5, can anyone explain why this is not happening?

#include <stdio.h>

void main()
{
   int a =2, b=3;
   b=a++ + b--;
   printf("a=%d  b=%d\n", a, b);
}

Answer 1

you are attempting to change b twice in the same expression

b = <something>;    // change b
    /*   b--  */    // change b

The order of the changes is not specified.