--x x-- ??????? help?

[dm6]

Hey guys, still anewbie here, someone was really helpful before! can someone please explain this to me?

Just wondering if you know this?

What is the difference between say --x and x-- in C++ code?

[Stupebrett]

If you do --x, x is decremented before any operation is done do it. If you do x--, it will be decremented after the operation.

#include <iostream>
using namespace std;

int main()
{
	int x = 2;

	cout << --x << endl;
	cout << x-- << endl;
	cout << x << endl;

	return 0;
}

As you can see with this program, the first cout will display 1, since x is decremented right away. The second will also display 1, since it first displays x's value, then decrement it. If we output x once more, we see that its value is now 0.

[dm6]

thankyou so much man !!!!

[Mathhead200]

It is a bit misleading to say it decrements after it returns. It actually decrements first but stores the original value and then returns that original value. The return must always happen last. x++ will often be optimized to ++x when the return value is not being used.