在建筑商方面,加上关键词explicit
,当节目设计者没有初衷时,便无法生成物体。 这种机制是否也可供投放者使用?
struct Foo
{
operator std::string() const;
};
比如,在这里,我希望能够加入<代码>。 Foo into a std:string
,但我不想暗中发生这种 cast。
在建筑商方面,加上关键词explicit
,当节目设计者没有初衷时,便无法生成物体。 这种机制是否也可供投放者使用?
struct Foo
{
operator std::string() const;
};
比如,在这里,我希望能够加入<代码>。 Foo into a std:string
,但我不想暗中发生这种 cast。
是的,无。
这取决于C++的哪一种版本,你重新使用。
explicit
type conversion operators例
struct A
{
//implicit conversion to int
operator int() { return 100; }
//explicit conversion to std::string
explicit operator std::string() { return "explicit"; }
};
int main()
{
A a;
int i = a; //ok - implicit conversion
std::string s = a; //error - requires explicit conversion
}
随附<代码>g++-std=c++0x,将出现这一错误:
赞成:13:20
But as soon as you write:
std::string s = static_cast<std::string>(a); //ok - explicit conversion
The error goes away : http://ideone.com/LhuFd
BTW在C++11中,如果将直线转换为Boolean,则明确转换操作者称为“正文转换操作者”。 此外,如果你想更多地了解暗含和明确的转变,就读到这个专题:
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