loop

[Sridhar Srinivasan]

For the following code, the answer given is 121212
class JMM110 {
public static void main (String[] args) {
int j = 0;
do for (int i = 0; i++ < 2
System.out.print(i);
while (j++ < 2);
}}

Can anybody pl explain?Thanks
[ May 22, 2004: Message edited by: Barry Gaunt ]

[Vicken Karaoghlanian]

I did a proper indentation for the code you've posted in order to make it easier to understand.

class JMM110 {
public static void main (String[] args) {

int j = 0;
 
do {

for (int i = 0; i++ < 2; ) {
System.out.print(i);
}

} while (j++ < 2);
}
}

Pay attention for the following:
1) do-while loop is always executed at least once.
2) i++ and j++ return its old value, then increment it.

Knowing this, give it another shot, and trace it again. If you still can't understand the answer, i'll explain it more in detail.
[ May 22, 2004: Message edited by: Vicken Karaoghlanian ]

[Voggy Horla]

the conditional expression
(i++ < 2)
will be executed before print the i.

[Barry Gaunt]

A good approach to understanding such problems is to run the code. You can also put additional print statements in to check the values of the variables i and j. There is also the technique of using a symbolic debugger such as that provided by the free Eclipse IDE. And there is also the java debugger jdb.

[Sridhar Srinivasan]

Hi!
I understood.Thanks a lot!