Java, returning a value from a method

Question

Im doing a simple piece of java code here, it is a method being called to convert Fahrenheit into Celsius. However when ever i run it, the output is always 0.0 .

I cant get it to output the correct calculation. There is probably some silly little thing i have forgotten to do, can someone please help me?

public class ExampleQ {

    public static void main(String[] args) {

        System.out.println(Celsius(50));
    }

    public static double Celsius(double F)
    {
        return (5 / 9) * (F - 32);
    }
}

Answer 1

The error is Integer division .

In Java 5 / 9 = 0

Try:

return (5.0 / 9) * (F - 32);

Answer 2

(5/9) produce an integer division with the result "0". As a result it produce 0 for whole expression. Try

return (5.0 / 9) * (F - 32);

Answer 3

Here is the solution. Tested at online compiler Ideone http://ideone.com/zRyG80

Just replace return (5 / 9) * (F - 32); with return (F - 32) * 5 / 9;

Because the reason is in the order of operators execution. In your code division is performed before multiplication which is making 5/9 = 0.

class Main {
    public static void main(String[] args) throws java.lang.Exception {

        System.out.println(Celsius(50));
    }

    public static double Celsius(double F) {
        return (F - 32) * 5 / 9;
    }
}

Output

10.0

Answer 4

5 / 9 returns 0, since you're performing integer division.

Use 5.0 / 9.0 instead

Answer 5

(5/9) is interpreted as integer and rounded to 0.0.

To avoid integer you can replace it with (5.0/9).

Answer 6

或者你可以使用下面的代码

return (5d / 9d) * (F - 32);