好吧,这是我第一次使用 lambda,我知道我可能会误用这个功能,但我想知道为什么会出现编译错误?
GameMap::MoveDirection AIPlayer::getSafeRouteTo(const GameMap::PlayerInfo& s, const Point& e)
{
struct node : public Point
{
GameMap::MoveDirection parent;
float d;
node():Point(){};
node(Point p) : Point(p)
{
};
};
auto lambdaFunction = [this,&e](node&left,node&right)->bool
{
return this->getDistance(left,e) + left.d < this->getDistance(right,e) + right.d;
};
priority_queue<node,vector<node>, decltype(lambdaFunction)> Q;
//do stuff
return GameMap::MD_None;
}
为了论证,让我说 MoveDirection 是一个枚举,而 Point 确实有一个默认构造函数。正如我通过删除该特定行评论的那样,我没有收到错误,但我真的需要它在那里。以下是 VC2010 生成的错误:
d:\program files (x86)\microsoft visual studio 10.0\vc\include\queue(225): error C2512: '`anonymous-namespace'::<lambda0>' : no appropriate default constructor available
1> d:\program files (x86)\microsoft visual studio 10.0\vc\include\queue(223) : while compiling class template member function 'std::priority_queue<_Ty,_Container,_Pr>::priority_queue(void)'
1> with
1> [
1> _Ty=AIPlayer::getSafeRouteTo::node,
1> _Container=std::vector<AIPlayer::getSafeRouteTo::node>,
1> _Pr=`anonymous-namespace'::<lambda0>
1> ]
1> c:\users\ali\documents\visual studio 2010\projects\bokhorbokhor\aiplayer.cpp(147) : see reference to class template instantiation 'std::priority_queue<_Ty,_Container,_Pr>' being compiled
1> with
1> [
1> _Ty=AIPlayer::getSafeRouteTo::node,
1> _Container=std::vector<AIPlayer::getSafeRouteTo::node>,
1> _Pr=`anonymous-namespace'::<lambda0>
1> ]
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