This week's book giveaway is in the Kotlin forum.We're giving away four copies of Kotlin in Action and have Dmitry Jemerov & Svetlana Isakova on-line!See this thread for details.
Win a copy of Kotlin in Action this week in the Kotlin forum!
programming forums Java Java JSRs Mobile Certification Databases Caching Books Engineering OS Languages Frameworks Products This Site Careers Other all forums
this forum made possible by our volunteer staff, including ...
Marshals:
Sheriffs:
Saloon Keepers:
Bartenders:

# Question

Vishal Arora
Greenhorn
Posts: 9
I got this question given below from a mock exam and i m not able to understand its output.Can somebody explain why its output will be "false true false true".
import java.io.*;

public class T026
{

public static void main(String args[])
{
System.out.print((1 - 1 / 3 * 3 ==0)+" "); //1

System.out.print((1 - 1.0f / 3.0f * 3.0f==0)+" "); //2

System.out.print((1 - 1.0f / 3.0f * 3.0d==0)+" "); //3

System.out.print((1 - 1.0d / 3.0d * 3.0d==0)+" "); //4
}
}

Sherry Jacob
Ranch Hand
Posts: 128
Hi,
Here are the answers to ur queries:
The first statement,
1 - 1 / 3 * 3
will be evaluated as follows:
1 - (1/3) * 3 = 1 - (0 * 3) = 1 - 0 = 1.
This is because in integer arithmetic operations, the division operator (/) has highest precedence followed by the multiplication operator (*) followed by Addition and Subtraction. Hence //1 returns false.

1 - 1.0f / 3.0f * 3.0f

Again, the evaluation proceeds as 1 - (1.0f / 3.0f) * 3.0f = 1 - (0.3333333... * 3) = 1 - 1 = 0. Thus //2 returns true.

1 - 1.0f / 3.0f * 3.0d

The evaluation proceeds as 1 - (1.0f / 3.0f) * 3.0d. But here we have a floating point and a double value. So the floating point operation is performed first...then converted to double...1 - 0.33333d * 3.0d. But converting from floating point to double causes some loss of precision and hence the result is <> 0. Hence //3 returns false.

Finally,
1 - 1.0d / 3.0d * 3.0d

returns true as all operations are with double values. Reasoning is much the same as at //2

Hope u got ur answers ?

Correct me if I was wrong anywhere.