排序算法

 

public static void 我的冒泡(){
		int [] arr = {4,9,23,1,45,27,5,2}; 
		for(int i=0;i<arr.length-1;i++){
			
			for(int j=0;j<arr.length-i-1;j++){
				if(arr[j] < arr[j+1]){
					int temp = arr[j];
					arr[j] = arr[j+1];
					arr[j+1] = temp;
				}
			}
		}
		for(int i=0;i<arr.length-1;i++){
			System.out.println(arr[i]);
		}
	}

public static void 選擇排序自己實現的(){
		int [] arr = {4,9,23,1,45,27,5,2}; 
		
		for(int i =0;i<arr.length-1;i++){
			int numindex = i;
			for(int j=i+1;j<arr.length;j++){
				if(arr[numindex]<arr[j]){
					numindex = j;//獲取大值  所以是倒敘
				}
			}
			int temp = arr[i];
			arr[i] =  arr[numindex];
			arr[numindex] = temp;
		}
		
		
		for(int i =0;i<arr.length;i++){
			System.out.println(arr[i]);
		}
	}

 

public static void 插入排序(Comparable []data){ 
		   //int [] arr = {4,9,23,1,45,27,5,2}; 
		    for(int index=1;index<data.length;index++){ 
		       Comparable key = data[index]; 
		       int position = index; 
		       while(position>0   &&   data[position-1].compareTo(key)>0){ 
			         data[position] = data[position-1]; 
			         position--; 
		       } 
		       data[position]=key; 
		   }   
		} 

 

對象排序
/**
 * Project Name:ThinkinJava
 * File Name:User.java
 * Package Name:org.cf.guott.java.beansort
 * Date:2013-10-29下午04:22:27
 * Copyright (c) 2013, [email protected] All Rights Reserved.
 *
*/

package org.cf.guott.java.beansort;
/**
 * ClassName:User <br/>
 * Function: TODO ADD FUNCTION. <br/>
 * Reason:	 TODO ADD REASON. <br/>
 * Date:     2013-10-29 下午04:22:27 <br/>
 * @author   gtt
 * @version  
 * @since    JDK 1.6
 * @see 	 
 */
public class User {

	private int age;
	private String name;
	
	public User(int age,String name){
		this.age = age;
		this.name = name;
	}
	public int getAge() {
		return age;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public void displayUser(){
		System.out.println("age="+age+";name="+name);
	}
}
/**
 * Project Name:ThinkinJava
 * File Name:UserArr.java
 * Package Name:org.cf.guott.java.beansort
 * Date:2013-10-29下午04:23:21
 * Copyright (c) 2013, [email protected] All Rights Reserved.
 *
*/

package org.cf.guott.java.beansort;
/**
 * ClassName:UserArr <br/>
 * Function: TODO ADD FUNCTION. <br/>
 * Reason:	 TODO ADD REASON. <br/>
 * Date:     2013-10-29 下午04:23:21 <br/>
 * @author   gtt
 * @version  
 * @since    JDK 1.6
 * @see 	 
 */
public class UserArr {

	private User[] users;
	private int nElems;
	
	public UserArr(int max){
		users = new User[max];
		nElems = 0;
	}
	public void insert(int age,String name)
	{
		users[nElems] = new User(age,name);
		nElems ++;
	}
	public void display(){
		for(int i =0;i<nElems;i++){
			users[i].displayUser();
		}
	}
	
	public void userSort(){
		for(int out = 1;out<nElems;out++){
			User u = users[out];
			int in = out;
			while(in > 0 && users[in - 1].getAge() > users[in].getAge()){
				users[in] = users[in -1];
				in --;
			}
			users[in]=u; 
		}
	}
	public static void main(String[] args) {
		UserArr arr = new UserArr(3);
		arr.insert(15,"aaa");
		arr.insert(27,"bbb");
		arr.insert(12,"ccc");
		arr.userSort();
		arr.display();
	}
}

 

輸出：
age=15;name=aaa
age=12;name=ccc
age=27;name=bbb