Stupidity and lack of understanding

[Apfelholz]

 

can anyone tell me why this is? all the explanations I have found have not helped me

[LapsedMemory]

5 minutes ago, Apfelholz said:

 

can anyone tell me why this is? all the explanations I have found have not helped me

Assuming you're asking why the one was flagged wrong and the other correct, the wrong one is because i starts out <10.  Think of that statement as a While loop. 

 

For the solution marked in green, think of it this way:

Set i to 0

While i is less than 20, i=i+2

Once i >=20, the loop ends

 

For the incorrect solution

Set i to 0

While i > 10, i=i+1

i isn't greater than 10 to start, so the computer can't start the loop to increment it.

 

I believe the ones marked in grey are all supposed to be checked (can't read the tags, but the logic is sound)

The first one not marked will never reach 0 because the loop always adds to i, and the other one not marked doesn't increment i at all.

[wanderingfool2]

What was the question?

 

Generally for loops though the parameters are

starting value

condition to keep going

changing of value

 

So in cases like i > 0 you should be having the value getting smaller

 

Going top to bottom here:

1) counts 0.5, 1.5, ... , 11.5 (since it's adding one)

2) Loop keeps going until it rolls over the integer 10, 11, ..., MAX_INT (because starting at 10 and incrementing by 1 each time would make it always greater than 0)

3) Goes from 20, 19,,,,0 (since i >= 0)

4) The one you selected, does run.  Since it starts at i = 0 but i > 10...so 0 > 10, which is false at the very beginning

5) Goes from 0, 1, ..., 9

6) Goes from 1, 3, ... 7, 9 (since starting at 1 and incrementing by 2 each time)

7) Goes from 0, 2, .... 18 (since it starts at 0, increments 2 each time)

[Apfelholz]

thank you now I have done it right in the nest attempt