How does one represent the empty char?

Question

I\'m currently writing a little program but I keep getting this error when compiling

error: empty character constant

I realize i

Answer 1

To represent the fact that the value is not present you have two choices:

1) If the whole char range is meaningful and you cannot reserve any value, then use char* instead of char:

char** c = new char*[N];
c[0] = NULL; // no character
*c[1] = ' '; // ordinary character
*c[2] = 'a'; // ordinary character
*c[3] = '\0' // zero-code character

Then you'll have c[i] == NULL for when character is not present and otherwise *c[i] for ordinary characters.

2) If you don't need some values representable in char then reserve one for indicating that value is not present, for example the '\0' character.

char* c = new char[N];
c[0] = '\0'; // no character
c[1] = ' '; // ordinary character
c[2] = 'a'; // ordinary character

Then you'll have c[i] == '\0' for when character is not present and ordinary characters otherwise.

Answer 2

There is no such thing as the "empty character" ''.

If you need a space character, that can be represented as a space: c[i] = ' ' or as its ASCII octal equivalent: c[i] = '\040'. If you need a NUL character that's c[i] = '\0'.

Answer 3

The empty space char would be ' '. If you're looking for null that would be '\0'.

Answer 4

String before = EMPTY_SPACE+TAB+"word"+TAB+EMPTY_SPACE;

Where EMPTY_SPACE = " " (this is String) TAB = '\t' (this is Character)

String after = before.replaceAll(" ", "").replace('\t', '\0');

means after = "word"

Answer 5

You can't store "no character" in a character - it doesn't make sense.

As an alternative you could store a character that has a special meaning to you - e.g. null char '\0' - and treat this specially.

Answer 6

There are two ways to do the same instruction, that is, an empty string. The first way is to allocate an empty string on static memory:

char* my_variable = "";

or, if you want to be explicit:

char my_variable = '\0';

The way posted above is only for a character. And, the second way:

#include <string.h>
char* my_variable = strdup("");

Don't forget to use free() with this one because strdup() use malloc inside.