初學者的問題 各位大哥幫忙解決一下

Question

using System;class IfApp
{
    public static int Main(string[] args)
    {
        
        if (args.Length < 1)
        {
            Console.WriteLine("Usage: ifApp char");
            return 1;
        }
        char chLetter = args[0][0];
        if (chLetter >= 'A')
        {
                   if (chLetter <= 'Z')
            {
                Console.WriteLine("{0} 岆跺湮迡趼譫", chLetter);
                return 0;
            }
        }        if (chLetter >= 'a' && chLetter <= 'z')
        {
            Console.WriteLine("{0} 岆跺苤迡趼譫", chLetter);
            return 0;
        }
        if (Char.IsDigit(chLetter))
        {
            Console.WriteLine("{0} 岆跺杅趼", chLetter);
            return 0;
        }&#63483;
        Console.WriteLine("{0} 岆跺杻忷趼睫", chLetter);
        return 1;
    }
}誰幫我解釋這段程序啊﹗特別是chLetter = args[0][0];﹐為什么帶兩個括號啊 

Answer 1

string类型你可以理解成char[]，
所以string[] 就可以有args[][]的用法

Answer 2

using System;class IfApp
{
    public static int Main(string[] args)\\传入参数
    {
        
        if (args.Length < 1)  \\传入参数为空
        {
            Console.WriteLine("Usage: ifApp char");
            return 1;
        }
        \\字符串数组转换为字符数组
        \\取第一个字符
        char chLetter = args[0][0];
        \\判断是否是大写字母
        if (chLetter >= 'A')
        {
                   if (chLetter <= 'Z')
            {
                Console.WriteLine("{0} 岆跺湮迡趼譫", chLetter);
                return 0;
            }
        }
\\判断是否是小写字母
        if (chLetter >= 'a' && chLetter <= 'z')
        {
            Console.WriteLine("{0} 岆跺苤迡趼譫", chLetter);
            return 0;
        } \\是否是数字
        if (Char.IsDigit(chLetter))
        {
            Console.WriteLine("{0} 岆跺杅趼", chLetter);
            return 0;
        }&#63483;
        Console.WriteLine("{0} 岆跺杻忷趼睫", chLetter);
        return 1;
    }
}