char* text = "Hello!"
can be thought of as the following:
At program start, you create an array of chars, 7 in length:
{'H','e','l','l','o','!','\0'}
. The last one is the null character and shows that there aren't any more characters after it. [It's more efficient than keeping a count associated with the string... A count would take up perhaps 4 bytes for a 32-bit integer, while the null character is just a single byte, or two bytes if you're using Unicode strings. Plus it's less confusing to have a single array ending in the null character than to have to manage an array of characters and a counting variable at the same time.]
The difference between creating an array and making a string constant is that an array is editable and a string constant (or 'string literal') is not. Trying to set a value in a string literal causes problems: they are read-only.
Then, whenever you call the statement char* text = "Hello!"
, you take the address of that initial array and stick it into the variable text
. Note that if you have something like this...
char* text1 = "Hello!";
char* text2 = "Hello!";
char* text3 = "Hello!";
...then it's quite possible that you're creating three separate arrays of {'H','e','l','l','o','!','\0'}
, so it would be more efficient to do this...
char* _text = "Hello!";
char* text1 = _text;
char* text2 = _text;
char* text3 = _text;
Most compilers are smart enough to only initialize one string constant automatically, but some will only do that if you manually turn on certain optimization features.
Another note: from my experience, using delete []
on a pointer to a string literal doesn't cause issues, but it's unnecessary since as far as I know it doesn't actually delete it.