public class TimedComputation {
        
   /* This program performs some mathematical computations and displays
      the results.  It then reports the number of seconds that the 
      computer spent on this task.
   */

   public static void main(String[] args) {

     long startTime;   // Starting time of program, in milliseconds.
     long endTime;     // Time when computations are done, in milliseconds.
     double time;      // Time difference, in seconds.
     
     startTime = System.currentTimeMillis();
     
     double width, height, hypotenuse;  // sides of a triangle
     width = 42.0;
     height = 17.0;
     hypotenuse = Math.sqrt( width*width + height*height );
     System.out.print("A triangle with sides 42 and 17 has hypotenuse ");
     System.out.println(hypotenuse);
     
     System.out.println("\nMathematically, sin(x)*sin(x) + cos(x)*cos(x) - 1 should be 1.");
     System.out.println("Let's check this for x = 1:");
     System.out.print("      sin(1)*sin(1) + cos(1)*cos(1) - 1 is ");
     System.out.println( Math.sin(1)*Math.sin(1) + Math.cos(1)*Math.cos(1) - 1 );
     System.out.println("(There can be round-off errors when computing with real numbers!)");
     
     System.out.print("\nHere is a random number:   ");
     System.out.println( Math.random() );
     
     endTime = System.currentTimeMillis();
     time = (endTime - startTime) / 1000.0;
     
     System.out.print("\nRun time in seconds was:  ");
     System.out.println(time);

   } // end main()
} // end class TimedComputation