实现 IComparable 接口的 C# 程序

C# 提供了一个 IComparable 接口。该接口提供了不同类型的特定类型比较方法，这意味着值类型或类可以实现该接口来对其实例进行排序，因为我们无法直接对类的实例进行排序，因为编译器不知道在哪个基础上进行排序。同样，直接比较两个实例会引发编译器错误，因为编译器对要比较的内容感到困惑。

句法：

public interface IComparable

实现 IComparable 接口需要：

• 添加一个方法 CompareTo()，它接收一个对象并返回一个整数。
• 传入的对象首先被类型转换为类类型并存储在临时变量中。然后将其与当前方法的属性进行比较
• CompareTo() 方法取决于比较：
  • 如果当前实例的属性等于临时变量的属性，则返回 0
  • 如果当前实例的属性大于临时变量的属性，则返回 1
  • 如果当前实例的属性小于临时变量的属性，则返回 -1

现在让我们通过下面的示例讨论如何实现 IComparable 接口。

示例：下面是 IComparable 接口的实现。在此示例中，我们根据员工 ID 对员工进行排序。

C#

// C# program to demonstrate how to
// implement IComparable interface 
using System;
using System.Collections.Generic;
  
class GFG{
  
// Driver code
static public void Main()
{
      
    // Create an array of employees 
    // using collection initializer
    Employee[] employees = new Employee[]
    {
        new Employee(1, "Susmita"),
        new Employee(5, "Soniya"),
        new Employee(3, "Rohit"),
        new Employee(2, "Mohit"),
        new Employee(4, "Pihu")
    };
      
    // Displaying the employee's array before sorting
    Console.WriteLine("Before sorting employees array");
    foreach(var emp in employees)
    {
          Console.WriteLine("ID - {0}, Employee Name - {1}", 
                            emp.ID, emp.EmployeeName);
    }
      
    // Sorts the employees array in ascending 
    // order on basis of id of the employee
    Array.Sort(employees);   
        
    Console.WriteLine();
        
    // Printing the employee's array after sorting
    Console.WriteLine("After sorting employees array");
    foreach(var emp in employees)
    {
          Console.WriteLine("ID - {0}, Employee Name - {1}",  
                            emp.ID, emp.EmployeeName);
    }
}
}
  
// Implementing IComparable interface
public class Employee : IComparable{
      
public int ID;
public string EmployeeName;
  
// Employee constructor
public Employee(int id, string employeename)
{
    this.ID = id;
    this.EmployeeName = employeename;
}
  
// Implementation of the CompareTo() method which takes
// an object as an input and return integer value depending on
// the comparison between current object and incoming object,
public int CompareTo(object incomingobject)
{
      
      // Storing incoming object in temp variable of 
      // current class type
      Employee incomingemployee = incomingobject as Employee;
    
      return this.ID.CompareTo(incomingemployee.ID);
}
}

输出：

Before sorting employees array
ID - 1, Employee Name - Susmita
ID - 5, Employee Name - Soniya
ID - 3, Employee Name - Rohit
ID - 2, Employee Name - Mohit
ID - 4, Employee Name - Pihu

After sorting employees array
ID - 1, Employee Name - Susmita
ID - 2, Employee Name - Mohit
ID - 3, Employee Name - Rohit
ID - 4, Employee Name - Pihu
ID - 5, Employee Name - Soniya