0

In C# standard is written that exsists an implicit conversion between array according to the following rules:

From an array-type S with an element type SE to an array-type T with an element type TE, provided all of the following are true:

  • S and T differ only in element type. In other words, S and T have the same number of dimensions.

but if I make:

int[] j = { 1, 2 };
int[] k = { 1 };

k = j;

no compiler error is emitted. Maybe I didn't understand the meaning of this rule...

  • Both SE and TE are reference-types.

but, again, in the example above the element type of j and k are value types.

  • An implicit reference conversion exists from SE to TE.

here if I have:

int[] j = { 1, 2 };
short[] k = { 1, 5 };

j = k;

it seems like there can be an implicit conversion from element of type short to element of type int but the complier not compile. Emit an error.

Sincerely I can't figure how this rule work!

Improve this question
6
  • No conversion is required in this case, because both i and j are the same type, int[]. The dimensionality and element type are both identical. Commented Dec 28, 2015 at 10:00
  • 1
    Rule you quote simply does not apply here. Instead you should look at this: 6.1.1 Identity conversion An identity conversion converts from any type to the same type. This conversion exists such that an entity that already has a required type can be said to be convertible to that type. Commented Dec 28, 2015 at 10:08
  • @PetSerAl, but if I can't make k = j if j is short[] j and k is int[] k then all array conversions are implicity conversion of type identity conversion! Commented Dec 28, 2015 at 10:19
  • 1
    @xdevel2000 Implicit conversion from string[] to object[] is not an identity conversion. Commented Dec 28, 2015 at 10:26
  • 1
    @xdevel2000 Nor int, nor short are reference-types. And there is no implicit reference conversion between them. short to int conversion covered by 6.1.2 Implicit numeric conversions. Commented Dec 28, 2015 at 10:41

4 Answers 4

Reset to default
2

Both j and k are the same type. There are both an integer array, and they both have one dimension. So the array is entirely according to the rules.

These are the incorrect usings of the arrays as described in the documentation:

object[] j; int[] k;

int[,] j; int[] k;

float[] j; int[] k;
Improve this answer
Sign up to request clarification or add additional context in comments.

Comments

1

What this code does is that it makes both k and j point to the same array, { 1, 2 }

since both k and j are arrays with the same number of dimentions and the same element type, you can make one point to the other using this code

Improve this answer

Comments

0
  1. Your arrays has the same element types.
  2. Your arrays has value types in their elements.
  3. Your arrays has the same dimentions - one.
  4. Multi-dimensional arrays looks like this: int[,,] (3 dimentions).
Improve this answer

Comments

0

S and T refer to the type of the arrays. In which case, j and k are both type int[] so there is no implicit conversion because they are the same type.

Since they don't differ in element type, their dimensions are irrelevant.

Improve this answer

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.