I have this code snippet below. Is it correct to describe that sum will be 0 because sum++ will be ignored as assignment of sum += will be adding 0 before increasing the value? Or how is this best described? I mean if I use sum += sum + 1 the result is different.
int sum = 0; for (int i = 0; i < 10; i++) { sum += sum++; } // Sum has end value 0 sum++ increments the value, but it returns the value it was before it was incremented. ++sum increments the value as well, but returns the value after the incrementing.
You can think sum++ as returning the value, then increasing the value (even though that's not what's happening)
And you think ++sum as increasing the value and then returning it.
So, sum += ++sum is the same as sum += sum + 1, as far as final result goes.
In your example, sum++ returns zero, sum is set two 1, but then you set it back to 0 and it repeats.
suminto memory position 1 . Then it loads sum again into memory position 2. It then adds one to memory position 2 and stores the result tosum(without updating memory position 2). It then adds up memory positions 1 and 2 (both still 0) and assigns the result of that to sum so sum is 0 again.sum += ++sum;