# Shiqianfeng JAVA classes against the war, March 28 #

Shiqianfeng against the war in class for the first 13 days;
Saturday today, but to make a lucid lesson, so JAVA_DAY11;
today we ended the notepad to write code phase; started using eclipse to write code ;
learning courses are familiar with the eclipse routine use, and select the sort commonly used class of two-dimensional arrays;
Chinese world refuel refueling!!
I Come!

package homework;

import java.util.Arrays;
import java.util.Scanner;

import javax.swing.plaf.synth.SynthSpinnerUI;

/**
 * 次代码为今天学的剩余两种排序:选择排序+利用导包排序.
 */
public class Test1 {

	public static void main(String[] args) {
		Scanner sc =new  Scanner(System.in);
		System.out.println("请输入长度:");
		int len = sc.nextInt();
		int[] arr = new int[len];
		for(int i = 0;i<arr.length;i++){
			System.out.println("请输入第"+(i+1)+"个数:");
			arr[i] = sc.nextInt();
		}
//		函数调用选择排序.
		selectionSort(arr);
		
//		利用Java类来排序.
		Arrays.sort(arr);
		for(int e :arr){
			System.out.print(e+"\t");
		}
		System.out.println("main ... over");
	}
	/**
	 * 选择排序： 思路： 每一轮找个基准值：在基准值上放一个比较小的数.
	 * 定义一个变量k用于记录每轮最小值的下标,以便交换.
	 */
	public static void selectionSort(int[] arr){
		for(int i =0;i<arr.length;i++){
			int k=i;
			for(int j = k+1;j<arr.length;j++){
				if(arr[k]>arr[j])
					k=j;
			}
//			防止过度交换:因为一轮后k值没变的话,就没必要交换.
			if(k!=i){
				int temp = arr[i];
				arr[i] = arr[k];
				arr[k] = temp;
			}
		}
		for(int e :arr){
			System.out.print(e+"\t");
		}
		System.out.println("选择排序...over");
	}
}