CODEWITHSUNDEEP
java
Amnestyy
Amnestyy

Reputation: 17

Head First Java program explanation

my program and question are below

public class test {
    public static void main(String[] args) {
            int x = 0;
            int y = 0;
            while ( x < 5 ) {
                y = x - y;
                System.out.println(x + "" + y);
                x = x+1;
            }
        }
    }

So output for this is 00 11 21 32 42. I understand what happens when x is even but what when x is odd? Let's move to step 2 and make x=1, then we get 

 y=1-y 
2y=1
 y=1/2

For me output should be like 11/2 or sth like that So how the hell output for this is 11? Do we use approximation? Thanks for answer.

Upvotes: 0

Views: 189

Answers (3)

Milkmaid
Milkmaid

Reputation: 1754

Isn't it obvious? By "=" you assigning new value into variable.

    x = 0, y = 0
    y = 0 - 0 = 0
    print x y -> 0 0
    x = 1, y = 0
    y = 1 - 0 = 1
    print x y -> 1 1 
    x = 2, y = 1
    y = 2 - 1 = 1
    print x y -> 2 1

etc...

Upvotes: 1

Suresh Atta
Suresh Atta

Reputation: 122006

No. You understand it wrong. You are doing math keeping the fact aside that evaluation of Java expression. 

  y = x - y;

means 

y= 1-0;

Which is 

y = 1

Upvotes: 5

Luke Joshua Park
Luke Joshua Park

Reputation: 9806

There's nothing off with your code, the result is correct. When x is 1, we set y to be equal to x - y. That means x and y are both 1, as 1 - 0 is 1. Remember that a = b in programming is an assignment and does not imply equality.

Upvotes: 2

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