C ＃ fine sorting knowledge points 9 Set 2 (recommended Collection)

4. Stack

Stack ( Stack ) Is one of the common data structures , Stack is a first in and last out structure , That is, the element is inserted from the end of the stack , Remove from the end of the stack , It is similar to loading cars when moving in daily life , First load the things on the car and then take them down .

In the collection Stack Class simulates stack operations , Provides properties and methods commonly used in the stack .

Stack Class provides 3 Construction methods , As shown in the following table ：

Construction method	effect
Stack()	Use initial capacity to create Stack The object of
Stack(ICollection col)	establish Stack Example , This instance contains elements copied from the specified instance , And the initial capacity and the number of copied elements 、 Same growth factor
Stack(int capacity)	establish Stack Example , And set its initial capacity

Stack The common properties and methods in the class are shown in the following table ：

Properties or methods	effect
Push(object obj)	Add elements to the stack , Also called stack
object Peek()	Used to get the value of the top element of the stack , But do not remove the value of the top element of the stack
object Pop()	The value used to remove the top element of the stack , And remove the top element
Clear()	from Stack Remove all elements from
Contains(object obj)	To determine whether an element is present Stack in
object[] ToArray()	Copy Stack Into a new array

example ：

class Program
{
    static void Main(string[] args)
    {
         // Simulate the access of restaurant dishes .
        Stack stack = new Stack();
        // Put elements into the stack 
        stack.Push("1 Plate No ");
        stack.Push("2 Plate No ");
        stack.Push("3 Plate No ");
        stack.Push("4 Plate No ");
        stack.Push("5 Plate No ");
        Console.WriteLine(" Take out the plate ：");
        // Determine if there are elements in the stack 
        while(stack.Count != 0)
        {
            // Take out the elements in the stack 
            Console.WriteLine(stack.Pop());
        }
    }
}

5. Hashtable ( Hash table )

Hashtable Class implements the IDictionary Interface , The values in the collection are accessed in the form of key value pairs . Element order according to key Of hash Values .

C# Medium Hashtable Called hash table , Also known as hash table , Use key value pairs in this set （key/value） Store values in the form of .

Besides , It also provides information about the elements in the collection key Value to find its corresponding value The method of value .

Hashtable Class provides many construction methods , The most common construction method without parameters , That is, instantiate through the following code Hashtable class .

Hashtable  Object name  = new Hashtable();

Hashtable The properties and methods commonly used in the class are shown in the following table :

Properties or methods	effect
Count	The actual number of elements stored in the collection
void Add(object key,object value)	Add elements to the collection
void Remove(object key)	According to the designation key Value to remove the corresponding collection element
void Clear()	Empty the set
ContainsKey (object key)	Determines whether the set contains the specified key The value of the elements
ContainsValue(object value)	Determines whether the set contains the specified value The value of the elements

example ：

class Program
{
    static void Main(string[] args)
    {
        Hashtable ht = new Hashtable();
        ht.Add(1," Fundamentals of computer ");
        ht.Add(2,"C# Advanced programming ");
        ht.Add(3," Database application ");
        Console.WriteLine(" Please enter the book number ");
        int id = int.Parse(Console.ReadLine());
        bool flag = ht.ContainsKey(id);
        if(flag)
        {
            Console.WriteLine(" The name of the book you are looking for is ：{0}",ht[id].ToString());
        }
        else{
            Console.WriteLine(" The book number you are looking for does not exist ！");
        }
        Console.WriteLine(" All book information is as follows ：");
        foreach(DictionaryEntry d in ht)
        {
            int key = (int)d,key;
            string value = d.Value.ToString();
            Console.WriteLine(" Book number ：{0}, The name of the book ：{1}",key.value);
        }
    }
}

6. Ordered list

SortedList Class implements the IDictionary Interface , The values in the collection are accessed in the form of key value pairs .C# SortedList It is called a sequence table , according to key Value sorts the elements in the collection .

SortedList The properties and methods commonly used in the class are shown in the following table ：

Properties or methods	effect
Count	The actual number of elements stored in the collection
void Add(object key,object value)	Add elements to the collection
void Remove(object key)	According to the designation key Value to remove the corresponding collection element
void Clear()	Empty the set
ContainsKey (object key)	Determines whether the set contains the specified key The value of the elements
ContainsValue(object value)	Determines whether the set contains the specified value The value of the elements

example ：

class Program
{
    static void Main(string[] args)
    {
        SortedList st = new SortedList();
        st.Add(1," Xiao Zeng ");
        st.Add(2," Xiaojia ");
        st.Add(3," Xiaoyi ");
        Console.WriteLine(" Please enter the registration number ");
        int id = int.Parse(Console.ReadLine());
        bool flag = st.ContainsKey(id);
        if(flag)
        {
            string name = st[id].ToString();
            Console.WriteLine(" The name of the patient you are looking for is ：{0}",);
        }
        else{
            Console.WriteLine(" The registration number you are looking for does not exist ！");
        }
        Console.WriteLine(" All patient information is as follows ：");
        foreach(DictionaryEntry d in st)
        {
            int key = (int)d,key;
            string value = d.Value.ToString();
            Console.WriteLine(" Registration number ：{0}, full name ：{1}",key.value);
        }
    }
}