Question

It seems these two declarations are the same:

int[] array1 = {11, 22, 33};

and

int[] array2 = new int[] {11, 22, 33};

But what is the need of this part new int[] in the second sample?
Does it make difference?

Answer 1

There’s no difference in this case – but the first syntax is only available when declaring a variable. From the C# 4 spec section 12.6:

Array initializers may be specified in field declarations, local variable declarations, and array creation expressions.

(The “array initializer” is the bit in braces – and an array creation expression is the form where you specify new int[] or whatever.)

When you’re not declaring a local variable or a field (e.g. if you’re passing an argument to a method) you have to use the second form, or from C# 3.0 you can use an implicitly typed array:

Foo(new[] { 1, 2, 3} );