如何使用[]在C中声明指向const字符数组的Const指针

Question

The const wikipedia article states:

int *ptr; // *ptr is an int value
int const *ptrToConst; // *ptrToConst is a constant (int: integer value)
int * const constPtr; // constPtr is a constant (int *: integer pointer)
int const * const constPtrToConst; // constPtrToConst is a constant (pointer)

and

const int*       ptrToConst;     //identical to: int const *       ptrToConst,
const int* const constPtrToConst;//identical to: int const * const constPtrToConst

Great.

How does this apply if I use [] instead of * to declare an array? For example, how do I turn the following:

char s[] = "Hello";

into a "const pointer to const"?

Answer 1

You don't. First of all s is not a pointer, and because it's not a pointer you already can't change the array to "point" somewhere else.

So all you need is to make the contents of the array constant:

const char s[] = "Hello";

The above will declare s as an array of six constant char elements, and initialize the contents with the string "Hello" .

Answer 2

In C, when a qualifier is added to the array declaration then it qualifies the element type instead of array itself. C11 section: §6.7.3/9

If the specification of an array type includes any type qualifiers, the element type is so- qualified, not the array type.[...]

So, it is not possible to declare const array of const data type .