When to use Float vs Double in JAVA code?

Question

Can someone show me an example of example how I could use Double in the following code?

    public class HelloWorld {
       public static void main(String[] args) {

           System.out.println("Hello, World!");

           int myFirstNumber = (5+10) + (6*8);//Declaring an integer myFirstNumber
           int mySecondNumber = 10;
           int myThirdNumber = 3;
           int myTotal = myFirstNumber + mySecondNumber + myThirdNumber;

           System.out.println(myFirstNumber);//prints variable myFirstNumber
           System.out.println("myFirstNumber ");//
           System.out.println(myTotal);
       }

    }

What is 10 divided by 4? If you use `int` to code that answer, your result will be `2`. But the answer should probably be `2.5`, don't you think. So **any** time you need non-integer numbers, use `double`. — Andreas, Jan 06 '17 at 07:21

score 0 · Answer 1 · answered Jan 06 '17 at 07:24

Use either float or double (or their boxed counterparts, Float and Double) when you need to deal with non-integer values. The code you posted has no apparent need for that, so it's hard to answer your question. But one possibility would be if you wanted to compute, say, the average of the three numbers:

public class HelloWorld { public static void main(String[] args) {
    System.out.println("Hello, World!");

   int myFirstNumber = (5+10) + (6*8);//Declaring an integer myFirstNumber
   int mySecondNumber = 10;
   int myThirdNumber = 3;
   int myTotal = myFirstNumber + mySecondNumber + myThirdNumber;
   float average = myTotal / 3.0f;

   System.out.println(myFirstNumber);//prints variable myFirstNumber
   System.out.println("myFirstNumber ");//
   System.out.println(myTotal);
   System.out.println(average);
}

As to when to use float vs. double (the title of your question), use double when you can tolerate less rounding error than you get with float.

When to use Float vs Double in JAVA code?

1 Answers1