Java help.

covana2244

Member

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Joined

Jul 5, 2004

Location

UNK Nebraska

• Jan 25, 2005

• #1

I need help. I have to write a java program to test a list of double numbers for whole values. Like if the number is 1.0 or 34.0 print to screen but if it is 1.3243 or 2.433 do not. How would I do this?

 

T

TimP

Member

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Joined

Jul 11, 2004

Location

Palatine, IL

• Jan 25, 2005

• #2

You could do something like this:

Code:

double[] x = {1.0, 3.45, 6.74, 5.0, 20.23, 1.423, 6.0, 19.0};

for(int i = 0; i < x.length; i++)
     if(Math.round(x[i]) == x[i])
          System.out.println(x[i]);

 

OP

covana2244

Member

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Joined

Jul 5, 2004

Location

UNK Nebraska

• Jan 26, 2005

• Thread Starter
• #3

The only problem is that I may have to compare over a billion of numbers. I ran a for loop for a billion times and sent the counter variable in to a method that contained an equation. I need to only output the values that are whole integer values.

 

fatguy

Member

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Joined

Jun 4, 2002

Location

New York City

• Jan 26, 2005

• #4

you should use the modulus operation:

Code:

public boolean testForWhole(double number) {
   return (number % 1.0 == 0);
}

This basically says that if when you divide the Double by 1 and there is no remainder (modulus), then return true. If there is a remainder, return false