C#常用数据结构之数组Array

int[] arr1 = new int[5];//声明带5个元素的数组
//或者
int[] arr2 = new int[] { 1, 3, 5, 7, 9 };
//或者
int[] arr3 = { 1, 3, 5, 7, 9 };

Person[] arrPerson = new Person[2];
arrPerson[0] = new Person {"a","af"}；
Person[] arrPerson2 = {new Person {"a","af"},new Person {"c","cf"}}

int a = arr1[0];//整数索引。
arr1[3] = 7;

for (int i = 0; i < arr1.Length; i++)
{
    Console.WriteLine(i + "," + arr1[i]);
}
//或者
foreach (int item in arr2)
{
    Console.WriteLine(item);
}

int[,] arr1 = new int[2, 3];//两行三列
int[,] arr2 = { { 1, 2, 3 }, { 4, 5, 6 } };

arr1[0, 2] = 25;//为数组的第一行第三列元素赋值为25

for (int i = 0; i < arr1.GetLength(0); i++)
{
    for (int j = 0; j < arr1.GetLength(1); j++)
    {
        Console.WriteLine(i + "," + j + "," + arr1[i, j]);
    }
}

int[][] arr1 = new int[][]
{
   new int[] { 1, 2 },new int[] {3,4,5}
};

arr1[0] = new int[] { 1, 2 };
arr1[1] = new int[] { 3, 4, 5 };

for (int i = 0; i < arr1.Length; i++)
{
    for (int j = 0; j < arr1[i].Length; j++)
    {
        Console.WriteLine(i + "," + j + "," + arr1[i][j]);
    }
}

Array array = Array.CreateInstance(typeof(int), 5);//相当于 int[] array=new int[5];
for (int i = 0; i < 5; i++)
{
    array.SetValue(33, i);
}
for (int i = 0; i < 5; i++)
{
    Console.WriteLine(array.GetValue(i));
}

public static void Sort (Array array, int index, int length);

void Main()
{
    Person[] ArrPerson = { new Person("ab", "bb"), new Person("ca", "ab") };
    Array.Sort(ArrPerson);
    foreach (Person p in ArrPerson)
    {
        Console.WriteLine(p);
    }
}

public class Person : IComparable
{
    public string FirstName;
    public string LastName;
    public Person(string firstName, string lastName)
    {
        this.FirstName = firstName;
        this.LastName = lastName;
    }
    public int CompareTo(object obj)
    {
        Person other = obj as Person;
        int result = this.LastName.CompareTo(other.LastName);//如果实例应排在参数对象前面，返回负数；如果实例应排在参数对象后面，返回整数；如果实例与参数对象相等，返回0；
        if (result == 0)
        { result = this.FirstName.CompareTo(other.FirstName); }
        return result;
    }
}

public static void Sort (Array array, int index, int length, System.Collections.IComparer comparer);

void Main()
{
    Person[] ArrPerson = { new Person("ab", "bb"), new Person("ca", "ab") };
    Array.Sort(ArrPerson, new PersonComparer());
    foreach (Person p in ArrPerson)
    {
        Console.WriteLine(p);
    }
}
public class Person
{
    public string FirstName;
    public string LastName;
    public Person(string firstName, string lastName)
    {
        this.FirstName = firstName;
        this.LastName = lastName;
    }
}

public class PersonComparer : IComparer
{
    public int Compare(object x, object y)
    {
        Person p1 = x as Person;
        Person other = y as Person;
        int result = p1.LastName.CompareTo(other.LastName);
        if (result == 0)
        { result = p1.FirstName.CompareTo(other.FirstName); }
        return result;
    }
}