Pls can someone tell me why the answer is 30 and not 27.

Question

int i=6;
for(i;i<=9;i++){}
Cout << 3*i;

Answer 1

It's too simple!
The value of i is equal to 9 then i increment by 1 and its equal to 10
Finally 3*10=30

Answer 2

because the condition is <= 9, to break this condition i need to be more than 9. since the increment is 1 i is 10 in the last itteration then check the condition again. the condition is false, the loop ended, and i still 10.

i i <=9 i++
6 -> 6<=9 (YES) -> 6+1
7 -> 7<=9 (YES) -> 7+1
8 -> 8<=9 (YES) -> 8+1
9 -> 9<=9 (YES) -> 9+1
10 -> 10<=9 (NO)
---> Loop end

Answer 3

The third part of the for loop is executed before checking the condition.

Let's jump to when i is 8, since until then everything should be clear. The contents of the loop get executed (nothing), then i is incremented (i = 9); i <= 9 is still true, so the loop continues, then it's incremented again (i = 10), but then the condition is false so the loop stops executing. 3 * 10 is 30, so the output is 30.