Array Syntax Versus Pointer Syntax

From what I've read, the following two definitions do the same thing:

Code:

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char str[] = "Example string";
char* str = "Example string";

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But what about when you want to define a string of a specific length, like this:

Code:

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char str[20];

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Is it possible do this with pointer syntax? Or would I have do to something like this:

Code:

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char string[20];
char* str = string;

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Those are not the same:

Code:

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char str[] = "Example string";  //the type of str is char[15]
char* str = "Example string";  //the type of str is char*

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Furthermore, in the second case it's a char* to an immutable string array. It should be declared as const char*, and the compiler lets you get away without the const only for obscure legacy reasons.

Code:

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char string[20];
char* str = string;

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Yes, here str is a pointer to the first character in the array of 20 characters called string.

Quote:

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Originally Posted by anon

Those are not the same:

Code:

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char str[] = "Example string";  //the type of str is char[15]
char* str = "Example string";  //the type of str is char*

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Right, I realize that one is an array and one is a pointer. What I meant is that they both define strings set to the same thing, even if one is the string itself and one is a pointer to it.

Quote:

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Originally Posted by LyTning94

Is it possible do this with pointer syntax? Or would I have do to something like this:

Code:

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char string[20];
char* str = string;

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If that's literally what you want, then yes. To declare a pointer to the beginning of some fixed-size buffer, you would do the above.

Quote:

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Originally Posted by LyTning94

Is it possible do this with pointer syntax? Or would I have do to something like this:

Code:

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char string[20];
char* str = string;

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It is not possible to use some special pointer syntax to indicate size because a pointer is just that - it points to something. It has no notion of size.
The above is only way to do what you want if you need a fixed-size buffer and a pointer to it (but why would you want a pointer to it?).

Quote:

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Originally Posted by Elysia

(but why would you want a pointer to it?).

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In the example I was reading, it used a pointer to a string so it could increment and loop through the characters, like this:

Code:

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char string[20];
char* str = string;

cin.get(str, 20);

for (int i = 0; i < 20; i++)
{
    cout<< *(str++) << endl;
}

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but I guess you could just do this instead:

Code:

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char string[20];

cin.get(string, 20);

for (int i = 0; i < 20; i++)
{
    cout<< *(string+i) << endl;
}

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Quote:

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Originally Posted by LyTning94

but I guess you could just do this instead:

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You could, but then you might as well write string[i] instead of *(string+i). Incidentally, be careful about using the name string in case you conflict with std::string.