multiplication in java by using *=?

Question

(i += 1) is equivalent to i = i + 1

is it possible to have something like above by using multiplication like:

(i *= 1) , i = i * 1

I have try it by declare as double but I keep get 0.0 value in my result?

You can use debugger to get the value of i just before multiplication and just after multiplication. Yes it is possible. — Shankhoneer Chakrovarty, Jul 15 '12 at 16:20

score 3 · Answer 1 · answered Jul 15 '12 at 15:57

3

It sounds like you're multiplying zero by one.

0 * 1 = 0

answered Jul 15 '12 at 15:57

SLaks

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Then any solution that can do as the way like above – cchua Jul 15 '12 at 15:58
@cchua: Do you understand what the problem is? – SLaks Jul 15 '12 at 15:59
ya I know because I declare the value as 0 so it keep multiply 0. So do you have any other way to do as this rather then just using the `*=` – cchua Jul 15 '12 at 16:02
2

@cchua Do *what*? If it's zero no matter what you multiply it by, or how, the result will be zero. – Dave Newton Jul 15 '12 at 16:13

score 2 · Accepted Answer · edited May 23 '17 at 10:34

First declare double i = 1.0; (or int i = 1; if no decimal values are needed.) It seems that you're multiplying by zero. Of course, then i times 1 will always be 1 unless you're modifying the value of i somewhere else.

Other than that, be aware that i *= 1 is almost equivalent to i = i * 1. The devil is in the details, as the first form will perform an implicit conversion as per the Java Language Specification, section §5.1.3:

compound assignment expressions automatically cast the result of the computation they perform to the type of the variable on their left-hand side. If the type of the result is identical to the type of the variable, the cast has no effect. If, however, the type of the result is wider than that of the variable, the compound assignment operator performs a silent narrowing primitive conversion

score 1 · Answer 3 · answered Jul 15 '12 at 15:59

1

If i has no assigned value (other than zero) before multiplying then it will be 0*1 equals 0.

answered Jul 15 '12 at 15:59

Michael Besteck

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score 1 · Answer 4 · answered Jul 15 '12 at 16:00

Its taking the default value of double, as you have declared it in the class scope...

Try this...

class Test implements TestInterface {


        public static void main(String[] args){
            double i = 1;
            System.out.println(i *= 1);
        }
     }

multiplication in java by using *=?

4 Answers4