001package stdlib; 002/* *********************************************************************** 003 * Compilation: javac Stopwatch.java 004 * 005 * 006 *************************************************************************/ 007 008/** 009 * <i>Stopwatch</i>. This class is a data type for measuring 010 * the running time (wall clock) of a program. 011 * <p> 012 * For additional documentation, see 013 * <a href="http://introcs.cs.princeton.edu/32class">Section 3.2</a> of 014 * <i>Introduction to Programming in Java: An Interdisciplinary Approach</i> 015 * by Robert Sedgewick and Kevin Wayne. 016 */ 017 018 019 020public class Stopwatch { 021 022 private final long start; 023 024 /** 025 * Create a stopwatch object. 026 */ 027 public Stopwatch() { 028 start = System.currentTimeMillis(); 029 } 030 031 032 /** 033 * Return elapsed time (in seconds) since this object was created. 034 */ 035 public double elapsedTime() { 036 long now = System.currentTimeMillis(); 037 return (now - start) / 1000.0; 038 } 039 040}