冒泡排序

大的向后排

  int[] arr = {12,24,6,18,7,41,21,354,12};
        for (int i= 0;i<arr.length-1;i++){
            for (int j =0 ;j<arr.length-i-1;j++){
                int temp ;
                if (arr[j]>arr[j+1]){
                    temp =arr[j];
                    arr[j]=arr[j+1];
                    arr[j+1]=temp;
                }
            }
        }