课后作业08 -- 二分查找法 (课后修改)
int[] arr1 = new int[] { 1, 3, 4, 5, 6, 9, 13, 25, 36, 45, 67 ,79}; foreach (int i in arr1) Console.Write(i + " ");//遍历数组 Console.WriteLine(" \n数组长度为:" + arr1.Length + "\n请输入要查找的数字:"); int num; try { num = Convert.ToInt32(Console.ReadLine()); } catch(Exception ex) { Console.WriteLine("输入错误!! \n错误信息是:" + ex.Message); Console.ReadLine(); return; } if (arr1.Contains(num))//判断数组是否包含要查找的数 { int a = 0 , b = arr1.Length -1 ,c ; while (a <= b)//条件判断中含有a = b ,可以有效查找两头 防止死循环 { c = (a + b) / 2; if (arr1[c] == num) { Console.WriteLine("您要找的数字是数组第" + (c + 1) +"位。"); break; } else if (arr1[c] > num) b = c - 1;//已经判断中间位置不等于要查找的数 可以多移一位增加效率 else a = c + 1; } } else Console.WriteLine("您要查找的数字不在数组内!"); Console.ReadLine();