C++ strings: [] vs. *

Question

Been thinking, what\'s the difference between declaring a variable with [] or * ? The way I see it:

char *str = new char[100];
char str2[] = \"Hi world!\";
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Answer 1

Okay, I had left two negative comments. That's not really useful; I've removed them.

• The following code initializes a char pointer, pointing to the start of a dynamically allocated memory portion (in the heap.)

char *str = new char[100];

This block can be freed using delete [].

• The following code creates a char array in the stack, initialized to the value specified by a string literal.

char [] str2 = "Hi world!";

This array can be modified without problems, which is nice. So

str2[0] = 'N';
cout << str2;

should print Ni world! to the standard output, making certain knights feel very uncomfortable.

• The following code creates a char pointer in the stack, pointing to a string literal... The pointer can be reassigned without problems, but the pointed block cannot be modified (this is undefined behavior; it segfaults under Linux, for example.)

char *str = "Hi all";
str[0] = 'N'; // ERROR!

• The following two declarations

void upperCaseString(char *_str) {};
void upperCaseString(char [] _str) {};

look the same to me, and in your case (you want to uppercase a string in place) it really doesn't matters.

However, all this begs the question: why are you using char * to express strings in C++?