Division problem

[Tomm Schuman]

Why does the code below print 1.0 if heading is 50? The real answer is 1.8
Rad is a double and heading an int.

I'm trying to convert degrees to rad, tell me if there's a better way to do it than the one i use. Thx in advance

 if (heading360>0){
rad = 180/heading360/2;
}
System.out.println("π/" + rad); 

[Carol Enderlin]

If heading is an int, then the result of 180/50/2 will be truncated.

rad = 180/heading360/2;  
 

What about Math.toDegrees() and Math.toRadians()

Looking at the source of Math class :

 
public static double toDegrees(double angrad) {
    return angrad * 180.0 / PI;
}
public static double toRadians(double angdeg) {
    return angdeg / 180.0 * PI;
}
 

[Prashanth Lingala]

use the toRadians(double degrees) method...

for example

double radiansAngle = Math.toRadians(degreeAngle)

Regards
Prashanth Lingala

[Tomm Schuman]

O there was already a method which does that

I have had sin,cos,tan in school but I don't really know how to use them in programming. Could someone give me an example about how you calculate the X in the triangle below.

[Layne Lund]

Using a little bit of trigonometry, you can set up an equation:

sin(PI/4) = 10/x

Solving this for x, you get

x = 10 / sin(PI/4)

You can convert this almost directly into Java using the Math class:

double x = 10.0 / Math.sin(Math.PI / 4);

The Math class also provides methods for cosine, tangent, and other nifty mathematical functions. See the link provided above for the Javadocs for this class.

HTH

Layne
[ March 10, 2005: Message edited by: Layne Lund ]

[Surasak Leenapongpanit]

May be you like this Commons-Math Library.