判断键盘输入是数字、大写字母还是小写字母——C#学习笔记

以下代码将判断键盘输入字符是数字 还是字母：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;namespace ConsoleApp4
{using System;using System.Threading;public class BoolKeyTest{static void Main(){repeat:Console.Write("Enter a character: ");char c = (char)Console.Read();if (Char.IsLetter(c)){if (Char.IsLower(c)){Console.WriteLine($"这时一个小写字母{c}.");}else{Console.WriteLine($"这时一个小写字母{c}.");}}else if(Char.IsDigit (c)){Console.WriteLine($"这是一个数字{c}.");}else{  int s = Convert.ToInt32(c);Console.WriteLine($"{s} IS Not an alphabetic character.");}goto repeat;//ascii码10是换行，13是回车，所以每次输入字符，按回车键都会识别这两个Console.ReadLine();Console.ReadLine();}}/* Sample Output:汉字提示是字母Enter a character: XThe character is uppercase.Enter a character: xThe character is lowercase.Enter a character: 2The character is not an alphabetic character.*/}