array [j] = array [++j] + 10; 1

[prosper]

The whole program is here
class plus
{
public static void main(String args[])
{
int array[] = {0,1,2,3,4,5};
int j =1 ;
array[j] = array[++j]+10;
for (int m=0; m<array.length; m++)
System.out.println(array[m]);
}
}

A book tells me to calcuate the right side ++j first and become array[2] = 12;
But the jdk1.4 shows another result
Would anyone explain it?

 

[Stijn147]

Golden rule:
When a variable appears more then once in a statement,
never use statements with side-effects on that variable
within that statement.

The sequence of calculating the whole statement can be
different from compiler to compiler.

instead of:
array[j] = array[++j]+10;

write:
j++;
array[j] = array[j]+10;


It's a lot safer!