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c++stdstring

Value and size of an uninitialized std::string variable in c++

If a string is defined like this

std::string name;

What will be the value of the uninitialized string "name" and what size it would be?

Solution

  • Because it is not initialized, it is the default constructor that is called. Then :

    empty string constructor (default constructor) :

    Constructs an empty string, with a length of zero characters.

    Take a look : http://www.cplusplus.com/reference/string/string/string/

    EDIT : As stated in C++11, §21.4.2/1 :

    Effects: Constructs an object of class basic_string. The postconditions of this function are indicated in Table 63.

    -> Table 63
+-----------------------------------------------------------------------------+
| data()     | a non-null pointer that is copyable and can have 0 added to it |
+------------+----------------------------------------------------------------+
| size()     | 0                                                              |
+------------+----------------------------------------------------------------+
| capacity() | an unspecified value                                            |
+-----------------------------------------------------------------------------+