Encontrar el índice de inicio del rango especificado en C#

La estructura de rango se introduce en C# 8.0. Representa un rango que tiene índices de inicio y fin. Puede encontrar el índice de inicio del rango dado con la ayuda de la propiedad de inicio proporcionada por la estructura de rango.
Sintaxis: 
 

public property Index Start { Index get(); };

Aquí, Index representa el índice de inicio inclusivo del rango.
Ejemplo 1:
 

// C# program to illustrate the use
// of Start property of Range struct
using System;
 
namespace range_example {
 
class GFG {
 
    // Main Method
    static void Main(string[] args)
    {
 
        // Creating range
        // using Range Constructor
        var r1 = new Range(0, 5);
 
        // Creating range
        // using range operator
        Range r2 = 3..7;
 
        // Finding the Starting
        // index of r1 and r2 ranges
        // Using Start property
        var res1 = r1.Start;
        Console.WriteLine("Starting index of r1 range: " + res1);
 
        var res2 = r2.Start;
        Console.WriteLine("Starting index of r2 range: " + res2);
    }
}
}

Producción:
 

Starting index of r1 range: 0
Starting index of r2 range: 3

Ejemplo 2:
 

// C# program to illustrate how to use
// Start property of Range structure
using System;
 
namespace range_example {
 
class GFG {
 
    // Main Method
    static void Main(string[] args)
    {
        // Creating and initializing an array
        string[] arr = new string[8] {"Archery", "Badminton", "Cricket", "Bowling",
                                   "Boxing", "Curling", "Tennis", "Skateboarding"};
 
        // Creating ranges
        // Using Range(Index, Index)
        // Constructor
        var r1 = new Range(0, 3);
        var r2 = new Range(4, 7);
 
        // Finding the start index
        // of the specified range
        // Using Start property
        var res1 = r1.Start;
        var res2 = r2.Start;
        Console.WriteLine("Start Index of Range {0} is {1}"+
               " and the item is {2}", r1, res1, arr[res1]);
 
        Console.WriteLine("Start Index of Range {0} is {1}"+
               " and the item is {2}", r2, res2, arr[res2]);
    }
}
}

Producción:
 

Start Index of Range 0..3 is 0 and the item is Archery
Start Index of Range 4..7 is 4 and the item is Boxing