Strange answer after executing n++

Question

Why is the value of int d 25 and not 26 after executing the following code snippet?

int n = 20;
int d = n++ + 5;

Console.WriteLine(d);

Answer 1

n++ is the "post-increment operator", which only increments the value after its initial value has been used in the surrounding expression.

Your code is equivalent to:

int d = n + 5;
n = n + 1;

To increment the value before its value gets used, use ++n, the pre-increment operator.