1 //二分法 2 //假设顶一个已经排好序的数组，用户输入一个数，找出这个数的位置，没有则返回空 3 int[] nums = new int[10] { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 }; 4 int a = 0, b = nums.Length - 1, zj; 5 Console.WriteLine("请输入要查找的数："); 6 int n = Convert.ToInt32(Console.ReadLine()); 7 while (b >= a) 8 { 9     zj = (a + b) / 2;//中间数的下标10     if (nums[zj] == n)11     {12         Console.WriteLine("找到了，在第{0}个", zj + 1);13         break;14     }15     if (nums[zj] > n)16     {17         b = zj - 1;//把后面的数去掉18     }19     if (nums[zj] < n)20     {21         a = zj + 1;//把前面的数去掉22     }23 }

 1 //二维数组 2 int[,] score = new int[3, 5]; 3 for (int i = 0; i < 3; i++)//循环每一行 4 { 5     Console.WriteLine("请输入第{0}位同学的成绩：", i + 1); 6     score[i, 0] = i + 1;//学号 7     //每一列需要从用户输入读取 8     Console.Write("C#:"); 9     score[i, 1] = Convert.ToInt32(Console.ReadLine());10     Console.Write("网页：");11     score[i, 2] = Convert.ToInt32(Console.ReadLine());12     Console.Write("数据库：");13     score[i, 3] = Convert.ToInt32(Console.ReadLine());14     score[i, 4] = score[i, 1] + score[i, 2] + score[i, 3];//总分15 }16 //冒泡排序，以总分成绩排名，score[i,4]17 for (int i = 1; i <= 2; i++)18 {19     for (int j = 1; j <= 3 - i; j++)20     {21         if (score[j - 1, 4] < score[j, 4])22         {23 for (int k = 1; k <= 5; k++)//把每一行所有列里面的内容交换24 {25     int s = score[j - 1, k - 1];26     score[j - 1, k - 1] = score[j, k - 1];27     score[j, k - 1] = s;28 }29         }30     }31 }32 //打印这个二维数组33 Console.WriteLine("学号\tC#\t网页\t数据库\t总分");34 for (int i = 0; i < 3; i++)35 {36     Console.Write(score[i, 0] + "\t");37     for (int j = 1; j < 4; j++)38     {39         Console.Write(score[i, j] + "\t");40     }41 42     Console.Write(score[i, 4]);43     Console.Write("\n");44 }