What's the output of my loops

[JerryRong]

Guys I don't know the output of the following loop please help me out

for ( int = 10; i > 0; i--)
      {
      system.out.println ( i*2);
      }

and one more:

while( a < 20 )
{ a += 3; System.out.println( a ); }

Thanks!

[zeroliken]

for ( int = 10; i > 0; i--)

missing i in the declaration

Guys I don't know the output of the following loop please help me out

I think you should study how loops work before asking questions like these.. the codes you posted are very basic it should be easy enough for you alone

Even a book can show examples like these

for ( int i = 10; i > 0; i--)
    {
    system.out.println ( i*2);
    }

the output is the current iterative value multiplied to 2

while( a < 20 )
    { a += 3; System.out.println( a ); }

"if" the value of a is originally 0 the last output should be 18

[stultuske]

to find out the output of those few lines, why didn't you just run the code and check it yourself?

[rotten69]

Well, if you do copy the code you've just posted, it won't run and will give an error message because you missed giving the counter "i" a name in your loop.

See below:

for ( int = 10; i > 0; i--) -->  int i, not just int

Ok. What's happening in the loop is that i is going to decrement by 1 as long as it's greater than 0 and then be multiplied by 2.

1st iteration:   i = 10 and 10 > 0  --->> output: 10*2 = 20
 2st iteration:   i = 9 and 9 > 0  --->> output: 9*2 = 18

it will keep going until the condition is met in your loop. That'll be the 10th iteration when the condition is met. 

10th iteration:                ---->> output: 1*2 = 2

I hope this helps you with understanding for-loops.. They can be quite tricky!

[mrjillberth]

In your for-statement, you

System.out.println();

was made to

system.out.println();

. Observe capitalization because Java is case-sensitive.