Why use the params keyword?

Question

I know this is a basic question, but I couldn't find an answer.

Why use it? if you write a function or a method that's using it, when you remove it the code will still work perfectly, 100% as without it. E.g:

With params:

static public int addTwoEach(params int[] args) {     int sum = 0;     foreach (var item in args)         sum += item + 2;     return sum; } 

Without params:

static public int addTwoEach(int[] args) {     int sum = 0;     foreach (var item in args)        sum += item + 2;     return sum; } 

Answer 1

With params you can call your method like this:

addTwoEach(1, 2, 3, 4, 5); 

Without params, you can’t.

Additionally, you can call the method with an array as a parameter in both cases:

addTwoEach(new int[] { 1, 2, 3, 4, 5 }); 

That is, params allows you to use a shortcut when calling the method.

Unrelated, you can drastically shorten your method:

public static int addTwoEach(params int[] args) {     return args.Sum() + 2 * args.Length; } 

Answer 2

Using params allows you to call the function with no arguments. Without params:

static public int addTwoEach(int[] args) {     int sum = 0;      foreach (var item in args)     {         sum += item + 2;     }      return sum; }  addtwoEach(); // throws an error 

Compare with params:

static public int addTwoEach(params int[] args) {     int sum = 0;      foreach (var item in args)     {         sum += item + 2;     }      return sum; }  addtwoEach(); // returns 0 

Generally, you can use params when the number of arguments can vary from 0 to infinity, and use an array when numbers of arguments vary from 1 to infinity.