CODEWITHSUNDEEP
carraysstringchar
Ruslan Ver
Ruslan Ver

Reputation: 137

Identification: Is that a string?

I dont know if that a string or an array...

char str4[100] = { 0 };

That code is a string?

If yes what it printing?

Upvotes: 1

Views: 190

Answers (4)

R Sahu
R Sahu

Reputation: 206627

I dont know if that a string or an array...

It is definitely an array. It can also be a string since a string is an array of characters terminated by a null character in C.

You can use it as an array:

char str4[100] = { 0 };
str4[0] = 'a';

You can also use it as a string:

if ( strcmp(str4, "ABC") == 0 )
{
   // This string contains "ABC"
}

When an array of characters is not a string

You can create an array of characters that cannot be used like a string.

char str[4] = { 'a', 'b', 'c', 'd' };
if ( str[0] == 'a' ) // OK
{
   // Do something
}

if ( strcmp(str, "ABC") == 0 ) // Problem. str does not have a null character.
                               // It cannot be used like a string.
{
}

Upvotes: 3

Elias Van Ootegem
Elias Van Ootegem

Reputation: 76405

str4 is an array of char's, so yes: it can be a string. You're initializing it to {0}. This means the first element in the array is being initialized to a terminating nul character (the end of a string), the result being: str4 is a valid, albeit empty, string. Implicitly, the rest of the array will be initialized to 0, too BTW.

Printing this string is the same as printing an empty string:

printf("");

The code you posted is exactly the same as this:

char str4[100] = "";
//or this
char str4[100] = {0, 0, '\0'};//'\0' is the same as 0
//or even
char str4[] = {0, 0, ..., 0};//100 0's is just a pain to write...

Or, in case of a global variable:

char str4[100];

simply because objects that have static storage are initialized to their nul-values (integer compatible types are initialized to 0, pointers to NULL):

If an object that has static storage duration is not initialized explicitly, it is initialized implicitly as if every member that has arithmetic type were assigned 0 and every member that has pointer type were assigned a null pointer constant.

Either way, the short answer is: str4 is an empty string.

Upvotes: 2

Turn
Turn

Reputation: 7020

In C a string is just an array of bytes that follows a particular convention, namely that the array of bytes be terminated by a null character. In this case, if you try to print str4 with something like printf, you'll find it looks like an empty string because the first byte is a null character, terminating it immediately.

Upvotes: 1

ouah
ouah

Reputation: 145859

By definition in C a string is a contiguous sequence of characters terminated by and including the first null character. So here you array also represents a string of length 0.

Upvotes: 1

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