In C, can I initialize a string in a pointer declaration the same way I can initialize a string in a char array declaration?

c pointers arrays c-strings
aoeu picture aoeu · Oct 29, 2010 · Viewed 17.4k times · Source

Do these two lines of code achieve the same result? If I had these lines in a function, is the string stored on the stack in both cases? Is there a strong reason why I should use one over the other, aside from not needing to declare the null terminator in the first line of code?

char  s[] = "string";
char* s   = "string\0";

Answer

Bart van Ingen Schenau picture Bart van Ingen Schenau · Oct 29, 2010

No, those two lines do not achieve the same result.

char s[] = "string" results in a modifiable array of 7 bytes, which is initially filled with the content 's' 't' 'r' 'i' 'n' 'g' '\0' (all copied over at runtime from the string-literal).

char *s = "string" results in a pointer to some read-only memory containing the string-literal "string".

If you want to modify the contents of your string, then the first is the only way to go. If you only need read-only access to a string, then the second one will be slightly faster because the string does not have to be copied.

In both cases, there is no need to specify a null terminator in the string literal. The compiler will take care of that for you when it encounters the closing ".

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