[alpha_x]

So I have a problem where in I need to print out 10 digits but my code is only printing out 9? Any ideas?

int[] array = { 1,2, 3, 4, 5, 6, 7, 8, 9, 10 };
for (int i = 1; i < 10; i++)
{
System.out.println(array[i]);
}

I have no idea why this isn't working, any ideas?

[CasiOo]

your array starts at the index 0, not 1

[v0rtex]

Java's arrays are off-indexed so initialize i at 0 not 1, its looping from 1-9 when it should be looping from 0-9
EDIT: Too late!

This post has been edited by v0rtex: 24 May 2011 - 12:33 AM

[alpha_x]

Wow that was fast, thanks a lot, this worked

for (int i = 0; i < 10; i++) 
{
System.out.println(i+1); //to get 1-10 and not 0-9?
}

Output:

1
2
3
4
5
6
7
8
9
10

[pbl]

Wont work if you array contains something else than 1,2,3,4,5,6

You are printing i you should print what is in array[i] starting with i == 0

for(int i = 0; i < array.length; ++i)
  System.out.println("array[" + i + "] = " + array[i]);

This post has been edited by pbl: 24 May 2011 - 12:43 AM

[Tarkenfire]

pbl, on 24 May 2011 - 12:40 AM, said:

Wont work if you array contains something else than 1,2,3,4,5,6

You are printing i you should print what is in array[i] starting with i == 0

for(int i = 0; i < array.length; ++i)
  System.out.println(array[i]);

Serious question, was ++i just a typo or is it a java thing that I don't know?

[pbl]

Tarkenfire, on 24 May 2011 - 03:44 AM, said:

Serious question, was ++i just a typo or is it a java thing that I don't know?

In this context
++i
and
i++
are equivalent.
On some processors (and on many RISC architecture) ++i might be executed in one or two less cycles than i++. So performance oriented programmers will always use ++i or --i version when they are equivalent to the i++ and i-- version.

a[i++] = 0; is not equivalent to a[++i] = 0;
but as increment/decrement of a for() loop it does not make a difference

[pbl]

Actually, if you really want to look like a pro

Most of the times, when you have to access an array in reverse order people code like this:

for(int i = array.length - 1; i >= 0; i--) {

now you just learned that this might be more efficient (at least in C/C++)

for(int i = array.length - 1; i >= 0; --i) {

People are used to the for() loop with 3 arguments. But the mos efficient way is like this

for(int i = array.length; --i >= 0; ) {

If you look at the code of the API you will see that the folks from Java Engineering usally use that syntax.

[v0rtex]

Useful tip pbl!

[pbl]

Not sure it will always make a difference, especially in Java, but when I see programmers's code using --i in a for() loop I suspect them to be also experience Assembler programmers so I trust a bit more their code .

This post has been edited by pbl: 24 May 2011 - 02:26 AM