What is meant by char temp[3]="";?

Question

Normally in C++, character arrays are initialized in the following way,

char example[5]="cat";

What if you initialize it with "" (just a double quotes without spaces)?
What will be the elements in the character array after initialization?

Answer 1

The declaration

char    temp[3] = "";

is same as

char    temp[3] = {0};
                  // `\0` ascii value is 0

remember remaining elements of half initialized array initialized with 0.

Point :char temp[3] = "" is easy to type(means writing), so its preferable.

Look even compare it with this declaration char temp[3] = {'\0'}; (it need more chars to type) Whereas in char temp[3] = ""; is simple (even no type mismatch - int/char).

Answer 2

It's a 3-character array initialized to three null characters.

EDIT (after comments below):

From K&R:

If there are fewer initializers for an array than the number specified, the missing elements will be zero for external, static, and automatic variables.

...

Character arrays are a special case of initialization; a string may be used instead of the braces and commas notation:

char pattern[] = "ould";

is a shorthand for the longer but equivalent

char pattern[] = { 'o', 'u', 'l', 'd', '\0' };

From a draft copy of the C++ standard, section 8.5.2, Character arrays:

"1. A char array (whether plain char, signed char, or unsigned char), char16_t array, char32_t array, or wchar_t array can be initialized by a narrow character literal, char16_t string literal, char32_t string literal, or wide string literal, respectively, or by an appropriately-typed string literal enclosed in braces. Successive characters of the value of the string literal initialize the elements of the array. [Example:

char msg[] = "Syntax error on line %s\n";

shows a character array whose members are initialized with a string-literal. Note that because ’\n’ is a single character and because a trailing ’\0’ is appended, sizeof(msg) is 25. — end example ]

...

"3. If there are fewer initializers than there are array elements, each element not explicitly initialized shall be zero-initialized (8.5)."

Answer 3

A blank string. The first char will be the null terminator. After an experiment, it appears the remaining characters are set to 0 (which is also null terminator).

Answer 4

You are setting the first element to be a null termination character. The other elements gain partial initialisation to zero: C and C++ : Partial initialization of automatic structure