从集合的末尾在C＃中的指定索引位置创建索引

索引结构在C＃8.0中引入。它表示可用于索引集合或序列的类型，并且可以从头开始或从头开始。您可以在Index结构提供的FromEnd(Int32)方法的帮助下创建结束索引。此方法从给定集合或序列的末尾在指定位置返回一个索引。

句法：

public static Index FromEnd(int value);

范例：1

// C# program to illustrate the 
// concept of the FromEnd() Method
using System;
  
namespace example {
  
class Program {
  
    // Main Method
    static void Main(string[] args)
    {
        // Creating end index
        // Using FromEnd() method
        var in1 = Index.FromEnd(2);
        var in2 = Index.FromEnd(1);
        var in3 = Index.FromEnd(0);
        var in4 = Index.FromEnd(6);
  
        // Display index value
        Console.WriteLine("Index position is : {0} ", in1);
        Console.WriteLine("Index position is : {0} ", in2);
        Console.WriteLine("Index position is : {0} ", in3);
        Console.WriteLine("Index position is : {0} ", in4);
    }
}
}

输出：

Index position is : ^2 
Index position is : ^1 
Index position is : ^0 
Index position is : ^6

范例2：

// C# program to illustrate the
// concept of the FromEnd() method
using System;
  
namespace example {
  
class GFG {
  
    // Main Method
    static void Main(string[] args)
    {
        // Creating and initializing an array
        string[] greetings = new string[] {"Hello", "Hola", "Namaste", 
                                "Bonjour", "Ohayo", "Ahnyounghaseyo"};
  
        // Creating end index
        // Using FromEnd() method
        var index_1 = Index.FromEnd(3);
        var index_2 = Index.FromEnd(1);
        var index_3 = Index.FromEnd(4);
        var index_4 = Index.FromEnd(5);
  
        // Displaying index and their values
        Console.WriteLine("Index: {0} Value: {1}", 
                     index_1, greetings[index_1]);
  
        Console.WriteLine("Index: {0} Value: {1}", 
                     index_2, greetings[index_2]);
  
        Console.WriteLine("Index: {0} Value: {1}", 
                     index_3, greetings[index_3]);
  
        Console.WriteLine("Index: {0} Value: {1}",
                     index_4, greetings[index_4]);
    }
}
}

输出：

Index: ^3 Value: Bonjour
Index: ^1 Value: Ahnyounghaseyo
Index: ^4 Value: Namaste
Index: ^5 Value: Hola