Menu
Is setting a string to '\0' the same thing as setting a string to NULL in other languages? Or... does setting a string to '\0' mean that the string is simply just empty?
char* str = '\0'
I have different functions to use for null strings and empty strings, so I don't want to accidentally call one of my empty string functions on a null string.
253
In practice, NULL is a constant equivalent to 0 , or "\0" . This is why you can set a string to NULL using: char *a_string = '\0'; Download my free C Handbook!
We can do this using the std::string::clear function. It helps to clear the whole string and sets its value to null (empty string) and the size of the string becomes 0 characters. string::clear does not require any parameters, does not return any error, and returns a null value.
If you want to zero the entire contents of the string, you can do it this way: memset(buffer,0,strlen(buffer));
\0 is zero character. In C it is mostly used to indicate the termination of a character string. Of course it is a regular character and may be used as such but this is rarely the case. The simpler versions of the built-in string manipulation functions in C require that your string is null-terminated(or ends with \0 ).
Your line char *str = '\0'; actually DOES set str to (the equivalent of) NULL. This is because '\0' in C is an integer with value 0, which is a valid null pointer constant. It's extremely obfuscated though :-)
Making str (a pointer to) an empty string is done with str = ""; (or with str = "\0";, which will make str point to an array of two zero bytes).
Note: do not confuse your declaration with the statement in line 3 here
char *str;
/* ... allocate storage for str here ... */
*str = '\0'; /* Same as *str = 0; */
which does something entirely different: it sets the first character of the string that str points to to a zero byte, effectively making str point to the empty string.
Terminology nitpick: strings can't be set to NULL; a C string is an array of characters that has a NUL character somewhere. Without a NUL character, it's just an array of characters and must not be passed to functions expecting (pointers to) strings. Pointers, however, are the only objects in C that can be NULL. And don't confuse the NULL macro with the NUL character :-)
134
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
