Question

Currently I am studying for my Java test. Whist studying I’ve come across a small problem.

In this for loop:

for ( int i=1; i <= 3 ; i++ ) {     for (int j=1; j <= 3 ; j++ ) {         System.out.println( i + ' ' + j );     } } 

The output is:

1 1 1 2 1 3 2 1 2 2 2 3 3 1 3 2 3 3 

My problem is, I don’t understand it. When I read this code I keep thinking it should look like this:

1 1 2 2 3 3 

Why is this not the case?

Answer 1

Each iteration of i, you’re starting a completely new iteration of j.

So, you start with i==1, then j==1,2,3 in a loop. Then i==2, then j==1,2,3 in a loop, etc.

Step through it one step at a time, and it will make sense.