TimedComputation.java

package nadine;
/**
* This program performs some mathematical computations and displays the
* results. It also displays the value of the constant Math.PI. It then
* reports the number of seconds that the computer spent on this task.
*/

public class TimedComputation {

	public static void main(String[] args) {
		long startTime; //Starting time of program, in nanoseconds.
		long endTime;	// Time when computations are done, in nanoseconds.
		startTime = System.nanoTime();
		
		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 0.");
		System.out.println("Let’s check this for x = 100:");
		System.out.print(" sin(100)*sin(100) + cos(100)*cos(100) - 1 is: ");
		System.out.println( Math.sin(100)*Math.sin(100)
		+ Math.cos(100)*Math.cos(100) - 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() );
		
		System.out.print("\nThe value of Math.PI is ");
		System.out.println( Math.PI );
		
		endTime =System.nanoTime();
		height = endTime - startTime;
		width = height / 1000000000.0;
		
		System.out.print("/nRun time in nanoseconds was: ");
		System.out.println(height);
		System.out.println("(This is probably not perfectly accurate!");
		System.out.print("/nRun time in seconds was: ");
		System.out.println(width);
	
	} // end main()	

} // end class TimedComputation