using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace test { class Program { static void Main(string[] args) { Console.WriteLine("请输入字符串:"); string str = Console.ReadLine(); int a1 = 0; foreach (var item in str) { if (int.TryParse(item.ToString(), out a1) == false) //判断是否是数字 { Console.Write(item.ToString()); } } Console.WriteLine("-----------------------------------");
int[][] num = new int[2][]; for (int i = 0; i < num.Length; i++) { num[i] = new int[9]; //声明第二数组长度 } for (int i = 0; i < num.Length; i++) { for (int j = 0; j < num[0].Length; j++) { num[i][j] = j + 1; //赋值 } } int a = 0, b = 0, c = 0; for (int i = 0; i < num[0].Length; i++) { for (int j = 0; j <= i; j++) { a = num[0][i]; b = num[1][j]; c = a * b; Console.Write(string.Format("{0}*{1}={2}\t ", a, b, c)); //按格式打印结果 } Console.WriteLine("\t"); } Console.WriteLine("-----------------------------------");
bool isSushu = true; int k; List<int> li = new List<int>(); Console.Write("正序打印50以内的素数:"); for (int i = 2; i < 50; i++) { k = 0; for (int j = 1; j < i; j++) { if (i % j == 0) { k++; if (k > 1) { isSushu = false; //判断是否是素数 } else { isSushu = true; } } } if (isSushu) { li.Add(i); //将结果添加到集合中 Console.Write(i + " "); } } Console.Write("\n倒序打印50以内的素数:"); var v = (from c2 in li orderby c2 descending select c2).ToList(); //查找结果并排序 也可以用循环来做 v.ForEach(s => Console.Write(s + " ")); //循环打印 Console.WriteLine("\n-----------------------------------"); List<StudentFenshu> Lsf = new List<StudentFenshu>(); StudentFenshu student; for (int i = 1; i < 5; i++) //获得学生信息 { student = new StudentFenshu(); try { Console.WriteLine("请输入第{0}学生姓名:", i); student.SName = Console.ReadLine(); Console.WriteLine("请输入该学生的语文成绩:(请输入数字)"); student.YuCJ = int.Parse(Console.ReadLine()); Console.WriteLine("请输入该学生的数学成绩:(请输入数字)"); student.SuCJ = int.Parse(Console.ReadLine()); Console.WriteLine("请输入该学生的英语成绩:(请输入数字)"); student.YuCJ = int.Parse(Console.ReadLine()); Lsf.Add(student); Console.WriteLine("保存成功!"); } catch (Exception e) { Console.WriteLine("输入参数类型错误!请重新输入" + e.ToString()); i--; } } Console.WriteLine("语文成绩由高到低的同学成绩如下:"); var yuwen = (from y in Lsf orderby y.YuCJ descending select new { y.SName, y.YuCJ }).ToList(); //查找对应结果并排序 yuwen.ForEach(s => Console.WriteLine(String.Format("{0}\t {1}", s.SName, s.YuCJ))); //打印结果,以下同上 Console.WriteLine("数学成绩由高到低的同学成绩如下:"); var shuxue = (from y in Lsf orderby y.SuCJ descending select new { y.SName, y.SuCJ }).ToList(); shuxue.ForEach(s => Console.WriteLine(String.Format("{0}\t {1}", s.SName, s.SuCJ))); Console.WriteLine("数学成绩由高到低的同学成绩如下:"); var yingyu = (from y in Lsf orderby y.EnCJ descending select new { y.SName, y.EnCJ }).ToList(); yingyu.ForEach(s => Console.WriteLine(String.Format("{0}\t {1}", s.SName, s.EnCJ))); Console.WriteLine("-------------------------------------------"); string userID = ""; string pwd = ""; int b4=0; bool JianYan = false; const string PWD = "admin123"; while (true) { Console.WriteLine("请输入用户名:(用户名不超过6位)"); userID = Console.ReadLine(); if (userID.Length > 6 || userID == "") //判断用户名长度及是否输入为空 { Console.WriteLine("用户名超过六位,请重新输入:"); } else { Console.WriteLine("请输入密码:(密码不能全部为数字:)"); pwd = Console.ReadLine(); foreach (var item in pwd) { if (int.TryParse(item.ToString(), out b4) == false) //判断密码类型 有字母则为真 否则为假 { JianYan = true; break; } else { JianYan= false; } } if (JianYan)//判断是否跟预定密码符合 { if (pwd == PWD) { Console.WriteLine("欢迎..."); break; } else { Console.WriteLine("密码错误!!请重新输入"); } } else { Console.WriteLine("密码不能全为数字,请重新输入"); } } }
} }
/// <summary> /// 定义学生类 /// </summary> public class StudentFenshu { public string SName{get;set;} public int YuCJ{get;set;} public int SuCJ{get;set;} public int EnCJ { get; set; } } }