<分区>
每个变量在使用前都应该被正确定义和初始化(给它赋值)。然而，在某些情况下，C++ 会将变量设置为默认值零。就像下面的案例。
class A{
...
static int val;
...};
//int val = 10; //This is the usual definition.
int val;//Definition without assigning a value.
...
A a; //a class A object
std::cout<<a.val;
结果将为零。显然，编译器将变量 a.val 初始化为零。我很好奇他们一般什么时候会这样做？
最佳答案
http://en.cppreference.com/w/cpp/language/zero_initialization
Zero initialization is performed in the following situations:
- For every named variable with static or thread-local storage duration, before any other initialization.
- As part of value-initialization (i.e. with an empty pair of parentheses or braces) sequence for non-class types and for members of value-initialized class types that have no constructors.
- When a character array is initialized with a string literal that is too short, the remainder of the array is zero-initialized.
关于c++ - 在什么情况下，c++ 会将变量初始化为零？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20403041/