基础加强第三天 练习总结

5、数字转大写案例

#region 练习：把123转换为：壹贰叁。Dictionary<char,char>

//提示用户输入

Console.WriteLine("请输入一个数");

//接受用户的输入

string number = Console.ReadLine();

string str = "1壹 2贰 3叁 4肆 5伍 6陆 7柒 8捌 9玖 0零";

Dictionary<int, char> dic = new Dictionary<int, char>();

//去掉字符串中的空格

string[] parts = str.Split(new char[]{' '},StringSplitOptions.RemoveEmptyEntries);

//加入键值对集合中

for (int i = 0; i < parts.Length; i++)

{

dic.Add(parts[i][0],parts[i][1]);

}

StringBuilder sb = new StringBuilder();

for (int i = 0; i < number.Length; i++)

{

sb.Append(dic[number[i]]);

}

Console.WriteLine(sb.ToString());

Console.ReadKey();

#endregion

#region 第二种方法

string str = "1壹 2贰 3叁 4肆 5伍 6陆 7柒 8捌 9玖 0零";

Dictionary<char, char> dic = new Dictionary<char, char>();

//去除空格

string[] number = str.Split(new []{' '},StringSplitOptions.RemoveEmptyEntries);

//将数组中的这十项都拿出来

for (int i = 0; i < number.Length; i++)

{

//将这十项添加到键值对字典中

//因为键不能重复，所以添加判断

if (!dic.ContainsKey(number[i][0]))

{

dic.Add(number[i][0],number[i][1]);

}

}

//提示用户输入

Console.WriteLine("请输入数字");

string txt=Console.ReadLine();

for (int i = 0; i < txt.Length; i++)

{

//判断当前字典中是否包含用户输入的数字

if (dic.ContainsKey(txt[i]))

{

//如果有这个值，那么久替换成大写 dic[txt[i]]这个代表当前这个键的值，打印输出

Console.Write(dic[txt[i]]);

}

else

{

//否则原样输出

Console.Write(txt[i]);

}

}

Console.ReadKey();

#endregion

#region 练习四 计算字符串中每种字母出现的次数（面试题）。 “Welcome ,to Chinaworld”，不区分大小写，打印“W2”“e 2”“o 3”……

string str = "Welcome ,to Chinaworld";

str = str.ToLower();

Dictionary<char, int> dic = new Dictionary<char, int>();

for (int i = 0; i < str.Length; i++)

{

if (char.IsLetter(str[i]))

{

if (!dic.ContainsKey(str[i])) //如果字典中不包含这个字符

{

//则添加这个字符，并且该字符出现的次数是1次

dic.Add(str[i], 1);

}

else

{

//键对应的值次数加1

dic[str[i]]++;

}

}

}

foreach (KeyValuePair<char,int> item in dic)

{

Console.WriteLine("字母{0}出现{1}次",item.Key,item.Value);

}

Console.ReadKey();

#endregion

6、文件操作

//写入文件

//using (FileStream fs=new FileStream("5.txt",FileMode.OpenOrCreate,FileAccess.Write))

//{

// string str = "今天天气好晴朗";

// byte[] buffer = System.Text.Encoding.UTF8.GetBytes(str);

// fs.Write(buffer,0,buffer.Length);

//}

//Console.WriteLine("OK");

//Console.ReadKey();

//读取文件

using (FileStream fs=new FileStream("5.txt",FileMode.OpenOrCreate,FileAccess.Read))

{

byte[] buffer=new byte[fs.Length];

fs.Read(buffer,0,buffer.Length);

string msg = System.Text.Encoding.UTF8.GetString(buffer);

Console.WriteLine(msg);

}

Console.ReadKey();

7、工资翻倍

#region 练习3：通过StreamReader和StreamWrite对工资文件进行操作

//将文件中的工资翻倍再写入到文件中

using (StreamReader sr=new StreamReader("salary.txt",Encoding.Default))

{

using (StreamWriter sw=new StreamWriter("a.txt",false,Encoding.Default))

{

string line;

while ((line=sr.ReadLine())!=null)

{

string[] msg = line.Split(new char[]{'|'},StringSplitOptions.RemoveEmptyEntries);

string str = string.Format("{0}|{1}",msg[0],Convert.ToInt32(msg[1])*2);

sw.Write(str);

}

}

}

Console.WriteLine("ok");

Console.ReadKey();

#endregion

8、Path类

//1.

//string lujing = @"c:\1.txt";

////主要是更该后缀名

//string msg = Path.ChangeExtension(lujing,".rar");

//Console.WriteLine(msg);

//Console.ReadKey();

//2.合并路径

//string str1 = @"C:\Program Files (x86)\";

//string str2 = @"Microsoft SQL Server\100\SDK\Assemblies";

//string msg = Path.Combine(str1,str2);

//Console.WriteLine(msg);

//Console.ReadKey();

//3.查找某个文件所在的路径

string str = @"C:\Program Files (x86)\Microsoft SQL Server\100\SDK\Assemblies";

string msg = Path.GetDirectoryName(str);

Console.WriteLine(str);

Console.ReadKey();

//Path.GetExtension();//返回扩展名

//Path.GetFileName();//获得文件名

//Path.GetFullPath();//返回指定字符串的绝对路径