This week's book giveaway is in the Jobs Discussion forum. We're giving away four copies of Java Interview Guide and have Anthony DePalma on-line! See this thread for details.

Class test{ public static void main(String arg[]) { int x=0,y=0; for(int z=0;z<5;z++) { if((++x>2)||(++y>2)) { x++; } } System.out.println(x + " " +y); }

}

I traced it as follows

z=0- x=1,y=1; z=1 x=2,y=2; z=3 x=3 ,y=2 (Here x is >2 so x++ executed and now x is 4); z=4 x=5 y=2(Here also x+ executed and x is 6 now)

So o/p should be x=6and y=2 but why it is mentioned in answers as

x=8 and y=2?

One more is

Class test{ public static void main(String arg[]) { int x=0,y=0; for(int z=0;z<5;z++) { if((++x>2)&&(++y>2)) { x++; } } System.out.println(x + " " +y); }

}

I traced it as follows

z=0 x=1 y=0 z=1 x=2 y=0 z=2 x=3 y=1(the && condition is true so x++ evaluated and x is now 4) z=3 x=5 y=2(here x++ excecuted and x is 6 now) z=4 x=7 y=3

so o/p should be x=7 and y=3 right? but it is mentioned as x=6 and y=3

U missed one value of z. thats why you have got wrong answer

Analyse like

z=0-->x=1,y=1 z=1-->x=2,y=2 z=2-->x=3,y=2 once ++x ie ++2 becomes 3 xbecomes 4 x=4 z=3-->x=5,y=2 here in loop X becomes 6 z=4-->x=7,y=2 here in loop x becomes 8

z=0 x=1 y=0 z=1 x=2 y=0 z=2 x=3 y=1(the && condition is true so x++ evaluated and x is now 4) z=3 x=5 y=2(here x++ excecuted and x is 6 now) z=4 x=7 y=3

so o/p should be x=7 and y=3 right? but it is mentioned as x=6 and y=3

At z=2, you say that "&& condition is true", but the y>2 condition actually returns false for another two iterations of the loop. The if's block does not execute until z=4.

Les Hayden

vatsalya rao
Ranch Hand

Joined: Feb 14, 2007
Posts: 63

posted

0

Thank you all for pointing out ,where I went wrong.

It's a bit confusing this thing, but i got to the following conclusion:

z: 0 x: 1 y: 0 -> in the if condition, x is incremented z: 1 x: 2 y: 0 -> again, the same thing z: 2 x: 3 y: 1 -> x is incremented again, so the first part of the teste is true, making y also be incremented (just remembering here that y was not incremented before because && does not check the second statement if the first is false) z: 3 x: 4 y: 2 -> same situation explained in the las step z: 4 x: 6 y: 3 -> now we have the if scope executed so x is incremented 2 times.