Csharp/C Sharp/Language Basics/params

Check the array length for params parameters

 
using System;
public class Employee {
    public Employee(params string[] _name) {
        switch (_name.Length) {
            case 1:
                name = _name[0];
                break;
            case 2:
                name = _name[0] + " " + _name[1];
                break;
            default:
                break;
        }
    }
    public void GetName() {
        Console.WriteLine(name);
    }
    private string name = "";
}
public class Employeenel {
    public static void Main() {
        Employee bob = new Employee("Bob", "Wilson");
        bob.GetName();
    }
}

Normal parameter and params parameters

 
using System;
public class Starter {
    public static void Main() {
        Names("F", "F", "B", "A");
        Names("F", 1234, 5678, 9876, 4561);
        Names("F", "C", "D");
    }
    public static void Names(string company,params string[] employees) {
        Console.WriteLine("{0} employees: ",company);
        foreach (string employee in employees) {
            Console.WriteLine(" {0}", employee);
        }
    }
    public static void Names(string company,params int[] emplid) {
        Console.WriteLine("{0} employees: ",company);
        foreach (int employee in emplid) {
            Console.WriteLine(" {0}", employee);
        }
    }
    public static void Names(string company,string empl1, string empl2) {
        Console.WriteLine("{0} employees: ",company);
        Console.WriteLine("  {0}", empl1);
        Console.WriteLine("  {0}", empl2);
    }
}

Params Array

 
using System;
using System.Collections.Generic;
using System.Text;
class Util {
    public static int Sum(params int[] paramList) {
        if (paramList == null) {
            throw new ArgumentException("Util.Sum: null parameter list");
        }
        if (paramList.Length == 0) {
            throw new ArgumentException("Util.Sum: empty parameter list");
        }
        int sumTotal = 0;
        foreach (int i in paramList) {
            sumTotal += i;
        }
        return sumTotal;
    }
}
class Program {
    static void Entrance() {
        Console.WriteLine(Util.Sum(10, 9, 8, 7, 6, 5, 4, 3, 2, 1));
    }
    static void Main() {
        try {
            Entrance();
        } catch (Exception ex) {
            Console.WriteLine("Exception: {0}", ex.Message);
        }
    }
}

Use params to mark parameter

 
using System;
class ParamsSample {
    static void PrintStrings(params String[] StringArray) {
        for (int i = 0; i < StringArray.Length; i++)
            Console.Write("{0} ", StringArray[i]);
        Console.WriteLine();
    }
    static void Main(String[] args) {
        String names = "K";
        PrintStrings("A");
        PrintStrings(names, "R", "S");
        PrintStrings("R", "E", "C", "S");
    }
}

use the params feature to write functions which accept a variable number of arguments

 
using System;
public class MainClass {
    public static void Main(string[] args) {
        int nSum;
        Console.WriteLine("{0}", SumArgs(out nSum, 1, 2, 3));
        int[] nArray = { 4, 5, 6 };
        Console.WriteLine("{0}", SumArgs(out nSum, nArray));
    }
    public static int SumArgs(out int nSum, params int[] list) {
        nSum = 0;
        foreach (int n in list) {
            nSum += n;
        }
        return nSum;
    }
}