冒泡排序

package demo;

public class MaoPao {
    public static void main(String[] args) {
        //定义一个数组
        int [] arr = {1,6,3,9,4,2,5,8,0,7};
        System.out.println("排序前：" + arrayToString(arr));

        /*

        //第一次比较
        for (int i = 0; i < arr.length - 1 - 0; i++) {
           if (arr [i] > arr [i + 1]){
               int temp = arr [i];
               arr [i] = arr [i + 1];
               arr [i + 1] = temp;
           }
        }
        System.out.println("第一次比较后：" + arrayToString(arr));

        //第二次比较
        for (int i = 0; i < arr.length - 1 - 1; i++) {
            if (arr [i] > arr [i + 1]){
                int temp = arr [i];
                arr [i] = arr [i + 1];
                arr [i + 1] = temp;
            }
        }
        System.out.println("第二次比较后：" + arrayToString(arr));

        //第三次比较
        for (int i = 0; i < arr.length - 1 - 2; i++) {
            if (arr [i] > arr [i + 1]){
                int temp = arr [i];
                arr [i] = arr [i + 1];
                arr [i + 1] = temp;
            }
        }
        System.out.println("第三次比较后：" + arrayToString(arr));

        //第四次比较
        for (int i = 0; i < arr.length - 1 - 3; i++) {
            if (arr [i] > arr [i + 1]){
                int temp = arr [i];
                arr [i] = arr [i + 1];
                arr [i + 1] = temp;
            }
        }
        System.out.println("第四次比较后：" + arrayToString(arr));
*/

        for (int x = 0;x < arr.length - 1;x ++){
            for (int i = 0; i < arr.length - 1 - x; i++) {
                if (arr [i] > arr [i + 1]){
                    int temp = arr [i];
                    arr [i] = arr [i + 1];
                    arr [i + 1] = temp;
                }
            }
        }
        System.out.println("排序后：" + arrayToString(arr));
    }

    public static String arrayToString(int [] arr){
        StringBuilder s = new StringBuilder();
        s.append("[");

        for (int i = 0; i < arr.length; i++) {
            if (i == arr.length - 1){
                s.append(arr [i]);
            }else {
                s.append(arr [i]).append(", ");
            }
        }
        s.append("]");
        String str = s.toString();
        return str;
    }
}