c ++中未初始化的std :: string变量的值和大小 [英] Value and size of uninitialized std::string variable in c++

问题描述

如果字符串定义如下

std::string name;

未初始化的字符串name的值将是多少？ p>

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

推荐答案

因为它没有被初始化，它是被调用的默认构造函数。然后：

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

空字符串构造函数（默认构造函数）：

构造一个长度为零字符的空字符串。

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

查看：http://www.cplusplus.com/reference/string/string/string/

EDIT：
如 C ++ 11，§21.4.2/ 1 中所述：

E ff ects：构造类 basic_string 的对象。该函数的后置条件如表63所示。

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                                            |
+-----------------------------------------------------------------------------+

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