3月13日 冒泡排序

冒泡排序：由大到小排列

  int[] shuzu = new int[] { 3, 1, 8, 4, 0, 5, 6 };
 for (int i = 0; i < 7; i++)
            {
                for (int j = i; j < 6; j++)
                {
                    if (shuzu[i] < shuzu[j + 1])
                    {
                        zhong = shuzu[i];
                        shuzu[i] = shuzu[j + 1];
                        shuzu[j + 1] = zhong;
                    }
                }
            }

            for (int i = 0; i < 7; i++)
            {
                Console.WriteLine(shuzu[i]);
            }
Console.ReadLine();

用foreach代替：

int[] shuzu = new int[] { 3, 1, 8, 4, 0, 5, 6 };
for (int i = 0; i < 7; i++)
            {
                for (int j = i; j < 6; j++)
                {
                    if (shuzu[i] < shuzu[j + 1])
                    {
                        zhong = shuzu[i];
                        shuzu[i] = shuzu[j + 1];
                        shuzu[j + 1] = zhong;
                    }
                }
            }

 foreach (int a in shuzu)//遍历数组
            {
                Console.WriteLine(a);
            }
Console.ReadLine();

例题：

//输入人数，输入每个人的成绩
 //需要最高分、最低分
 //去掉两个最高分，去掉两个最低分，求平均分。
 Console.Write("请输入班级人数：");
 int a = int.Parse(Console.ReadLine());
 double[]fen=new double[a];
for (int i=0;i<a;i++ )
            {
                Console.Write("请输入第"+(i+1)+"个人的成绩");
                fen[i] = double.Parse(Console.ReadLine());
            }

     double zhong;
    for (int i = 0; i < a; i++)
            {
                for (int j = i; j < a-1; j++)
                {
                    if (fen[i] < fen[j + 1])
                    {
                        zhong = fen[i];
                        fen[i] = fen[j + 1];
                        fen[j + 1] = zhong;
                    }
                }
            }
 Console.WriteLine("最高分是"+fen[0]);
 Console.WriteLine("最低分是" + fen[a-1]);
            double sum = 0;
            for (int i=2;i<a-2 ; i++)
            {
            sum+=fen[i];
            }
 Console.WriteLine("平均分是"+sum/(a-4));

                Console.ReadLine();