冒泡排序

具体的执行步骤请详细看注释！！！

package com.yongjar.test;

/**
 * @author yongjar
 * @date 2021/2/26
 *
 * 冒泡排序
 */
public class BubbleSort {

    public static void bubbleSort(int [] a) {
        int temp;
        // i=1 i<3 true
        // -*! i++ = 2; i<3 true
        // i++=3
        for (int i = 1; i < a.length; i++) {

            // j=0; j<3-1 true
            // j++=1; j<3-1 true
            // -*! j++=2; j<2 false 返回上一个for -*!
            // j=0; j<3-2 true
            //j=0 j<1 true
            for (int j = 0; j <a.length-i ; j++) {

                // a[0] 25  > a[0+1] 29 false ,返回执行for循环
                //a[1](29) > a[1+1](21) true
                //a[0](25) > a[0+1](21) true
                if (a[j] > a[j+1]) {

                    // temp = a[1](29)
                    //temp = a[0](25)
                    temp = a[j];
                    //a[1] = a[2](21)
                    //a[0] = a[1](21)
                    a[j] = a[j+1];
                    //a[2] = temp(29), 返回继续执行for循环-*!
                    //a[1] = temp(25)
                    a[j+1] = temp;

                }

            }

        }


    }

    public static void main(String[] args) {

        int [] shuzu = new int[3];



        shuzu[0] = 25;
        shuzu[1] = 29;
        shuzu[2] = 21;


        System.out.println ("排序前的数组为：\n");

        for (int j = 0; j < 3; j++) {
            System.out.print (shuzu[j] + " ");
        }


        System.out.println ();

        bubbleSort (shuzu);

        System.out.print ("排序后的数组为：\n");


        for (int j = 0; j < 3; j++) {
            System.out.print(shuzu[j] + " ");
        }


        System.out.println ();
    }

}