c#中所有的類型都來自object
int i = 9;
//object o = 4;
//o=new Student();//裝箱
// int i=Convert.ToInt32(o);//出箱static void Main(string[] args)
{
int[] arr = new int[5] { 1, 2, 3, 4, 5 };
Console.WriteLine(arr.Average().ToString());
Console.WriteLine(arr.Length.ToString());
for (int i = 0; i < arr.Length; i++)
{
Console.WriteLine(arr[i] + “\t”);
}
object[] arrobject = new object[3];
arrobject[0] = 3;
arrobject[1] = 4.4;
arrobject[2] = new User();
User u1 = (User)arrobject[2];
User[] users = new User[2];
users[0] = new User();
users[0].Name = "hell";
users[1] = new User();
users[1].Name = "llo";
foreach (User u in users)
{
Console.WriteLine("student's name:{0}", u.Name);
}
//冒泡排序
int[] scores = new int[5] { 12, 43, 52, 563, 21 };
for (int i = 0; i < scores.Length - 1; i++)
for (int j = 0; j < scores.Length - 1 - i; j++)
{
int tmp;
if (scores[j] > scores[j + 1])
{
tmp = scores[j];
scores[j] = scores[j + 1];
scores[j + 1] = tmp;
}
}
//foreach循環
foreach (int i in scores)
{
Console.WriteLine(i);
}
Email email = new Email();
string choice = "";
do
{
email.PickName();
choice = Console.ReadLine();
choice = choice.ToLower();//轉爲小寫
Console.WriteLine("input y or n");
}
while (choice.Equals("y"));
Console.WriteLine("input message and split by \n");//分割字符串
string s = Console.ReadLine();
string[] arrstring;
arrstring = s.Split(' ');
foreach (string str in arrstring)
{
Console.WriteLine(str);
}
//
ArrayList arrlist = new ArrayList();
arrlist.Add(2);
arrlist.Add(0);
arrlist.Add(new User());
int it = (int)arrlist[0];
arrlist.Insert(0, 20);//在索引處插入
arrlist.RemoveAt(0);//通過索引刪除
User u11 = new User();
u11.Account = "aaaaa";
u11.Banlance = 34.1;
User u2 = new User();
u2.Account = "bbbb";
u2.Banlance = 4.4;
Hashtable ht = new Hashtable();//hashtable 鍵值對類比於java map
ht.Add(u11.Account, u11);
ht.Add(u2.Account, u2);
foreach (object obj in ht.Keys)
{
Console.WriteLine(obj.ToString());
}
foreach (object obj in ht.Values)
{
User u = (User)obj;
Console.WriteLine(u.Account);
}
//另一種遍歷
foreach (DictionaryEntry en in ht)
{
Console.WriteLine("\t{0}", en.Key);
Console.WriteLine("\t{0}", ((User)en.Value).Banlance);
}
Dictionary<int, string> d = new Dictionary<int, string>();//類型安全的,與hashtable對應
d.Add(1, "hell");
d.Add(2, "llo");
}