Why is the for loop prefix not taken into consideration?

[Benjamin Scabbia]

Hi!

I was looking at this for loop

for ( int i = 0; i < 10; i++){/*print i*/}

It prints 0..9 - fine.

I then looked at this loop

for ( int i = 0; i < 10; ++i){/*print i*/}

It prints 0..9 - why? From what I understand ++i is a prefix, therefore by the time the for loop condition is checked, shoudln't i start with 1? So 1..9?

If I did this test in a print statement so:

int i=0;
System.out.print(++i) //this prints 1, so why doesn't this apply in the for loop?

[Ulf Dittmer]

The difference between ++i and i++ is only within that statement. The print statement is a separate statement, so it has no effect on it.

https://coderanch.com/how-to/java/PostIncrementOperatorAndAssignment might be of interest.

[Winston Gutkowski]

Benjamin Scabbia wrote:It prints 0..9 - why?

Because:

for (int i = 0; i < 10; i++){
   System.out.print(i);
}

is precisely equivalent to:

int i = 0;
while(i < 10) {
   System.out.print(i);
   i++;
}

apart from the fact that, in the second case, i is defined outside the loop.

Now, looking at that second loop, would it make any difference if it was ++i instead of i++?

HIH

Winston

[Benjamin Scabbia]

Winston Gutkowski wrote:

Benjamin Scabbia wrote:It prints 0..9 - why?

Because:

for (int i = 0; i < 10; i++){
   System.out.print(i);
}

is precisely equivalent to:

int i = 0;
while(i < 10) {
   System.out.print(i);
   i++;
}

apart from the fact that, in the second case, i is defined outside the loop.

Now, looking at that second loop, would it make any difference if it was ++i instead of i++?

HIH

Winston

Great answer thanks for helping me out!

Makes sense and of course, in the second loop using a prefix or postfix would make no difference

[Winston Gutkowski]

Benjamin Scabbia wrote:Great answer thanks for helping me out!

You're most welcome. Glad it helped.

Winston