A Simple Enumeration demo in java

Here is a code for simple enum in java.

enum Cal
{
ADD
{
public double compute(double a, double b)
{ return a+b; };
},
SUB
{
public double compute(double a, double b)
{ return a-b; };
},
MUL
{
public double compute(double a, double b)
{ return a*b; };
},
DIV
{
public double compute(double a, double b)
{ return a/b; };
},
MOD
{
public double compute(double a, double b)
{ return a%b; };
},
;

public abstract double compute(double a, double b);


public static void main(String[] ar)
{
String opName = ar[0].toUpperCase();
double a = Double.parseDouble(ar[1]);
double b = Double.parseDouble(ar[2]);

System.out.println(Cal.valueOf(opName).compute(a,b));
}
}

To execute this code type the above code in any text editor and compile it by the command javac Cal.java and execute it by command java Cal 10 ADD 20