所以我有这两个代码。一种叫做 MyTimer 和 SortCode。MyTimer 计算一段代码的经过时间，而 SortCode 读取一个文件并打印出排序后的代码。如何使用 MyTimer 查找每个排序代码的经过时间。
import java.io.*;
import java.util.*;
public class SortCode
{
public static void main(String[] args)
{
ArrayList<Integer> hold = new ArrayList<Integer>();
try(
//Open files
FileReader reader = new FileReader("TestData.txt");
Scanner in = new Scanner(reader);
FileWriter writer = new FileWriter("SortedData.txt");
PrintWriter out = new PrintWriter(writer);
)
{
while(in.hasNextLine())
{
String next = in.nextLine();
try
{
int n = Integer.parseInt(next);
hold.add(n);
}
catch(NumberFormatException e)
{
System.out.println("Invalid input " + next);
}
}
insertionSort(hold);
for(Integer i : hold)
out.printf("%7d\n", i);
}
catch(IOException e)
{
System.out.println("Error opening the files." + e);
System.exit(1);
}
}
public static <T extends Comparable<T>>
void selectionSort(List<T> table)
{
int size = table.size();
for(int i = 0; i < size - 1; i++)
{
int minPos = i;
T minValue = table.get(i);
for(int k = i + 1; k < size; k++)
{
T nextValue = table.get(k);
if( nextValue.compareTo(minValue) < 0)
{
minPos = k;
minValue = nextValue;
}
}
if(minPos != i)
{
T temp = table.get(i);
table.set(minPos,temp);
table.set(i, minValue);
}
}
}
public static <T extends Comparable<T>>
int binSearch(ArrayList<T> table, int low, int high, T value)
{
while(low <= high)
{
int mid = (low + high)/2;
int result = value.compareTo(table.get(mid));
if(result == 0)
return mid;
if(result < 0)
high = mid - 1;
else low = mid + 1;
}
return -low -1;
}
public static <T extends Comparable<T>>
void insertionSort(ArrayList<T> table)
{
int size = table.size();
for(int i = 1; i < size; i++)
{
T temp = table.remove(i);
int pos = binSearch(table, 0, i - 1, temp);
if(pos < 0)
pos = -pos - 1;
table.add(pos, temp);
}
}
public static <T extends Comparable<T>>
void mergeSort(List<T> table)
{
int size = table.size();
if(size <= 1)
return;
int size1 = size/2;
int size2 = size - size1;
List<T> v1 = new ArrayList<T>();
List<T> v2 = new ArrayList<T>();
for(int i = 0; i < size1; i++)
v1.add(table.get(i));
for(int i = 0; i < size2; i++)
v2.add(table.get(size1 + i));
mergeSort(v1);
mergeSort(v2);
int i1 = 0, i2 = 0;
int i = 0;
T value1 = v1.get(i1);
T value2 = v2.get(i2);
while(i1 < size1 && i2 < size2)
{
if(value1.compareTo(value2) <= 0)
{
table.set(i++, value1);
i1++;
if(i1 < size1)
value1 = v1.get(i1);
}
else
{
table.set(i++, value2);
i2++;
if(i2 < size2)
value2 = v2.get(i2);
}
}
int k;
if(i1 < size1)
{
for(k = i1; k < size1; k++)
table.set(i++, v1.get(k));
}
else
{
for(k = i2; k < size2; k++)
table.set(i++, v2.get(k));
}
}
}
这是我的计时器
public class MyTimer
{
private long elapsedTime;
private long startTime;
private boolean on;
/**
Create a time in the "not running" state and initialize its elapsed time to zero.
*/
public MyTimer()
{
this.on = false;
this.elapsedTime = 0L;
}
/**
Change the state of the timer to running, initialize its elapsed time and
set its start time
*/
public void start()
{
this.on = true;
this.elapsedTime = 0L;
this.startTime = System.nanoTime();
}
/**
If the timer is in the running state change its state to "not running" and
accumulate elapsed time. If the timer is in the "not running" state stop
has no effect.
*/
public void stop()
{
if(this.on)
{
this.on = false;
long currentTime = System.nanoTime();
this.elapsedTime += (currentTime - this.startTime);
}
}
/**
If the timer is in the "not running" state, change its state to running, but do
not reset its elapsed time. New running time will be accumulated with previous
running time.
*/
public void resume()
{
if(!this.on)
{
this.startTime = System.nanoTime();
this.on = true;
}
}
/**
Return the elapsed time that this timer has accumulated. If the
timer is in the running state, the elapsed time must be calculated.
If the timer is in the "not running" state the elapsed time was already
calculated by the stop function.
*/
public long getElapsedTime()
{
if (this.on)
{
long currentTime = System.nanoTime();
this.elapsedTime += (currentTime - this.startTime);
this.startTime = currentTime;
}
return this.elapsedTime;
}
/**
Return elapsed time of the current timer in the form of a string.
*/
public String toString()
{
String result = "" + this.getElapsedTime();
return result;
}
}