loops

[dangle126]

Can anybody help me with 2 these problems ?
1)
int count = 3;
while (count-- > 0)
cout << count << " ";

the output of this code is 2,1,0

But
2)int count = 3;
while (--count > 0)
cout << count << " ";

the output of this code is 2,1 .

Can you help me understand why it is?

[MikeyBoy]

Please use code tags when posting code, to make it more readable.

Do you understand the difference between --count and count-- ?

[dangle126]

yes. but in those 2 cases I am so confused. It is so different from what i've knew

[MikeyBoy]

Just think about it logically. If you know the difference between those two, then you'll know that they evaluate to different values, so that the expression (count-- > 0) will be true under different values of count from those for which (--count > 0) is true.

EDIT: Most people think they understand what the difference between pre-increment and post-increment is, but don't really. If the problem isn't making sense to you, I'd recommend looking up what the difference really is, in case you've misunderstood it.

[dangle126]

Ah! Could you know why the first case it appears 0, but in 2 it doesn't?

[MikeyBoy]

As I said:

If the problem isn't making sense to you, I'd recommend looking up what the difference really is, in case you've misunderstood it.

[dangle126]

x++ increments the value of variable x after processing the current statement.

++x increments the value of variable x before processing the current statement.

[dangle126]

We have the condition that count is always greater than 0. But in the situation 1, as I think the value count will never be 0.

[MikeyBoy]

x++ increments the value of variable x after processing the current statement.

++x increments the value of variable x before processing the current statement.

As I suspected - you've only half-understood it, in the vague kind of way that most people think they have.

To reiterate one more time:

I'd recommend looking up what the difference really is