Class Stopwatch

  • public class Stopwatch
    extends Object
    The Stopwatch data type is for measuring the time that elapses between the start and end of a programming task (wall-clock time). To measure the running time of a code fragment, construct a Stopwatch object, execute the code you want to time, and then call the elapsedTime() method to get the elapsed time in seconds.
       Stopwatch stopwatch = new Stopwatch();
       // do some computationally intensive calculation here
       double time = stopwatch.elapsedTime();

    See StopwatchCPU for a version that measures CPU time. For additional documentation, see Section 1.4 of Algorithms, 4th Edition by Robert Sedgewick and Kevin Wayne.

    Robert Sedgewick, Kevin Wayne
    • Constructor Detail

      • Stopwatch

        public Stopwatch()
        Initializes a new stopwatch.
    • Method Detail

      • elapsedTime

        public double elapsedTime()
        Returns the elapsed CPU time (in seconds) since the stopwatch was created.
        elapsed CPU time (in seconds) since the stopwatch was created
      • main

        public static void main​(String[] args)
        Unit tests the Stopwatch data type. Takes a command-line argument n and computes the sum of the square roots of the first n positive integers, first using Math.sqrt(), then using Math.pow(). It prints to standard output the sum and the amount of time to compute the sum. Note that the discrete sum can be approximated by an integral - the sum should be approximately 2/3 * (n^(3/2) - 1).
        args - the command-line arguments