Why an int* array can't be initialized directly but char* array can be?

Question

Why an int* array can't be initialized directly but char* array can be? I know they are not same but what's the exact difference that causes this to happen (please explain why)?

I know why it's not possible for int* p[] to be initialized directly.
I don't know how it's possible for char* name[]?

For example:

char* name[] = { "Mostafa Chamran", "Mehdi Zeinoddin", "Ebrahim Hemmat" };

and

int* p[3] = {1, 2, 3};

give error: invalid conversion

I didn't know what to search to find a related question so I don't know whether the same question exists or not

because `"string literal like this"` is a `const char *` but numeric constants are not `int *`s — phuclv, Sep 13 '14 at 10:01
`const char[]` is the same as `const char *`. It's only different when declaring variables — phuclv, Sep 13 '14 at 10:26
did you read all his sentence? How can a `const char` (a character) be cast into `char*` (a pointer)? — phuclv, Sep 13 '14 at 10:27
@user3783574: String literals are `const char[x]`, not `const char`. `"foo"` is `const char[4]`, for instance. `const char[z]` is castable to `char*`. — T.J. Crowder, Sep 13 '14 at 10:39
im not native speaker so do u mean it can be changed to by saying that its castable? or u mean it is const char* — user3783574, Sep 13 '14 at 10:41
@user3783574: `const char[x]` isn't `char *` but can be cast to it implicitly ("implicitly" = "without actually writing something saying 'do this cast'). — T.J. Crowder, Sep 13 '14 at 10:43
so there is a deference between BEING const char* and being castable to it i gguess? — user3783574, Sep 13 '14 at 10:46
@user3783574: Yes. For example, `int` is not `long`, but `int` can be *implicitly cast* to `long`. *(Note: If you don't do `@T.J.`, I don't get notified of your comment.)* — T.J. Crowder, Sep 13 '14 at 11:38

score 5 · Answer 1 · answered Sep 13 '14 at 09:54

5

The latter expression is an array of pointers. The error indicates that you are converting int to int*.

The expression should be

int arr[3]={1, 2, 3};

answered Sep 13 '14 at 09:54

Captain Giraffe

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i know that but what about char* name?why it can hold literals? but int* p cant hold numbers ? i mean why char* can hold literals but int* cant hold numbers arent they same like numbers? – user3783574 Sep 13 '14 at 10:07
2

@user3783574: Because [the type of a string literal is "array of `const char`"](http://stackoverflow.com/a/15508173/157247), which can be implicitly cast to `char*`. – T.J. Crowder Sep 13 '14 at 10:10

score 4 · Accepted Answer · edited May 23 '17 at 12:01

The entries you're giving for p aren't int* entries, they're int entries, so the type is incorrect (int isn't int*). The string literals you're giving for the name entries are const char [x] (where x is the length of the literal*), which can be implicitly cast to char*, so the types are acceptable and that works.

Since your p is an array of int*, the entries must be int* or implicitly castable to it, just like the entries for your name array of char* are implicitly castable to char*.

(* "foo" is const char[4], for instance — 'f', 'o', 'o', '\0'.)

Why an int* array can't be initialized directly but char* array can be?

2 Answers2