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