Stopwatch

java.lang.Object
- edu.princeton.cs.algs4.Stopwatch

```
public class Stopwatch
extends java.lang.Object
```
The Stopwatch data type is for measuring the time that elapses between the start and end of a programming task (wall-clock time). 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.

构造器概要

构造器
构造器说明

Stopwatch()
Initializes a new stopwatch.

方法概要

修饰符和类型	方法	说明
`double`	`elapsedTime()`	Returns the elapsed CPU time (in seconds) since the stopwatch was created.
`static void`	`main(java.lang.String[] args)`	Unit tests the `Stopwatch` data type.

从类继承的方法 java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- 构造器详细资料
  - Stopwatch
```
public Stopwatch()
```
    Initializes a new stopwatch.
- 方法详细资料
  - elapsedTime
```
public double elapsedTime()
```
    Returns the elapsed CPU time (in seconds) since the stopwatch was created.
    
    返回:
    
    elapsed CPU time (in seconds) since the stopwatch was created
  - main
```
public static void main(java.lang.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).
    
    参数:
    
    args - the command-line arguments