Command Line Parameters in Java (1)

You can pass parameters from the command line to a Java program as shown below. In the final example, a parameter of -1 is supplied. The square root of -1 is a complex number if I remember correctly. The answer given, NaN, stands for not a number:

andrew@UBUNTU:~/Java$ cat prog34.java

public class prog34
{
public static void main(String[] args)
  {
  double x = Double.parseDouble(args[0]);
  System.out.println
  ("The square root of " + x     
   + " is " + Math.pow(x,0.5));
  }
}
andrew@UBUNTU:~/Java$ javac prog34.java
andrew@UBUNTU:~/Java$ java prog34 4
The square root of 4.0 is 2.0
andrew@UBUNTU:~/Java$ java prog34 10
The square root of 10.0 is 3.1622776601683795
andrew@UBUNTU:~/Java$ java prog34 -1
The square root of -1.0 is NaN
andrew@UBUNTU:~/Java$