排序算法之—冒泡排序

冒泡排序 两层控制

1. 两层循环作冒泡，外层轮数做比较，比较轮数多少次总数减一来控制
2. 内层循环记次数，次数变化看轮数，每轮比较得一数，放在最后最值
   数，每轮要比多少次？比较总数要减一然后减掉外层去.

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实现冒泡排序代码块如下

public static void bubbleSort(DataWrap[] data) {        System.out.println("开始排序");        int arrayLength = data.length;        for (int i = 0; i < arrayLength - 1; i++) {            boolean flag = false;            for (int j = 0; j < arrayLength - 1 - i; j++) {                if (data[j].compareTo(data[j + 1]) > 0) {                    DataWrap temp = data[j + 1];                    data[j + 1] = data[j];                    data[j] = temp;                    flag = true;                }            }            System.out.println(java.util.Arrays.toString(data));            if (!flag)                break;        }

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创建测试数据类 如下：

public class DataWrap implements Comparable<DataWrap>{    int data;    String flag;    public DataWrap(int data,String flag){        this.data = data;        this.flag = flag;    }    public String toString(){        return data + flag;    }    //根据data实例变量来决定两个dataWrap的大小    @Override    public int compareTo(DataWrap dw) {        return this.data > dw.data? 1 : (this.data == dw.data? 0 : -1);    }}

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主方法创建DataWrap类对象生成测试数据 并调用冒泡排序实现如下：

public static void main(String[] args) {        DataWrap[] data = { new DataWrap(9, ""), new DataWrap(-16, ""),                new DataWrap(21, "*"), new DataWrap(23, ""),                new DataWrap(-30, ""), new DataWrap(-49, ""),                new DataWrap(21, ""), new DataWrap(30, "*"),                new DataWrap(30, "")};        System.out.println("排序之前：\n" + java.util.Arrays.toString(data));        bubbleSort(data);        System.out.println("排序之后：\n" + java.util.Arrays.toString(data));    }