Post increment question

Question

I've this code

static void Main(string[] args)
{
    int x = 20;
    int y = 35;
    x = y++ + x++;
    y = ++y + ++x;
    Console.WriteLine(x);
    Console.WriteLine(y);
    Console.ReadLine();
}

I expected the output to be x = 57 and y = 94. However, when executed it gave me 56 and 93. For some reason the post increment operator is not getting executed in line 3.

Is this because we are assigning the result of expressing in line 3 to x itself? Are there any other scenarios where the post increment operator would not result as expected.

Thanks.

Answer 1

int x = 20;
int y = 35;
// x = y++ + x++; this is equivalent of
tmp = 35 + 20; y++; x++; x = tmp;
// so here we have x = 55; y = 36
// y = ++y + ++x;
y ++; // 37
x ++; // 56;
y = x + y;
// so here we have y = 93, x = 56;