java冒泡排序

public class code_select {

    // 冒泡排序
    public static  void bubbleSort(int []arr){
        if (arr == null || arr.length < 2){
            return;
        }
        int N = arr.length;
        
        // 把外面的边界确定好来
        for(int end = N - 1 ;  end >= 0; end--){
            // 0 1   1 2   2 3，打个比方让0  1 比较
            for (int second = 1; second <= end; second++) {
                if(arr[second-1] > arr[second]){
                    swap(arr, second - 1 , second);
                }
            }
        }
    }


    public static  void  swap(int[] arr, int i , int j){
        int temp = arr[j];
        arr[j] = arr[i];
        arr[i] = temp;
    }

    public static  void  printArray(int [] arr){
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i] + " ");
        }
        System.out.println();
    }


    public static void main(String[] args) {
        int[] arr = {7, 1, 2, 3, 5, 8};
        printArray(arr);
        bubbleSort(arr);
        printArray(arr);

    }

}