Be The JVM (Head First)

[Tariq Ab]

I don't understand how we got the output?!!
What's the first output in line 14? how do we calculate what's the value coming out of the loop? line 12?!

public class Output {
public static void main(String[] args) {
Output o = new Output();
o.go();
}
void go() {
int y = 7;
for(int x = 1; x<8; x++){
y++;
if (x>4){
System.out.print(++y + " ");
}
if (y>14){
System.out.println("x = "+x);
break;
}
}
}
}

Answer is 13 15 x = 6

[John Jai]

In line #11 - you increment the value of y for every iteration in the for loop.

In line #12 - you check whether value of x is greater than 4. If so you increment the value of y.

In line #16 - you check whether value of y is greater than 14, If so then you use the break command to exit the for loop. Once a break is executed the for loop is terminated and the value of y will be 15 outside the for loop..

Try to run below program to understand it. If you work out with a pencil and paper you will understand it better.

public class Output {
public static void main(String[] args) {
Output o = new Output();
o.go();
}
void go() {
int y = 7;
for(int x = 1; x<8; x++){
y++;
System.out.println("Value of X is -> " + x + " .. and value of Y now is -> " + y);
if (x>4){
// System.out.println(++y + " ");
++y;
System.out.println("When value of X is -> " + x + " which is greater than 4 we increment the value of Y");
System.out.println("After incrementing the value of Y now is -> " + y);
}
if (y>14){
System.out.println("Value of Y is now greater than 14... so I am going to break the for loop");
System.out.println("Value of X while breaking for loop is x = "+x);
break;
}
}
System.out.println("Value of y after loop is -> " + y);
}
}

[Tariq Ab]

Thank you so much Sir,

Finally got it. had to read it a couple of times letter by letter.

Now i can go to bed