**Reusing the Wheel**

We are going to use the Visualizer in the previous article, Plotting Graph

All we have to do is to prepare a new data file named data.txt, which will contain the values of sin(x) for x=0,15,30,45,60... (degree).

**data.txt**

A few lines of the data file is shown, you may use a line editor to calculate the value of sin(x) up to 360 degree. Or you may use an excel spread sheet to generate the data.

0 0.2588 0.5 0.7071 0.8660 ...

**Automatic data generation**

If you don't like to use a spread sheet program, you may write a simple java program to generate the data. A simple example is shown below :

/****************************************************************************** * File : DataWriter.java * Author : http://java.macteki.com/ * Description : * Calculate y=sin(x) for x=0,15,30,..., 360 * Tested with : JDK 1.6 ******************************************************************************/ class DataWriter { public static void main(String[] args) throws Exception { double pi_over_180 = 3.141592654/180; for (double degree=0; degree<=360; degree+=15) { double radian = degree*pi_over_180; double sine = Math.sin(radian); System.out.println(sine); } } }Of course you would need to redirect the program output :

javac DataWriter.java java DataWriter > data.txt

**Plotting the Curve**

Once you have data.txt ready, you may invoke the Visualizer class to plot the curve. The Visualizer class is defined in the article Plotting Graph

java Visualizer

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