class Message
{
public:
std::string getHeader (const std::string& header_name) const;
// other methods...
};
class MessageSorter
{
public:
// take the field to sort by in the constructor
MessageSorter (const std::string& field) : _field( field ) {}
bool operator (const Message& lhs, const Message& rhs)
{
// get the field to sort by and make the comparison
return lhs.getHeader( _field ) < rhs.getHeader( _field );
}
private:
std::string _field;
};
std::vector<Messages> messages;
// read in messages
MessageSorter comparator;
sort( messages.begin(), messages.end(), comparator );
这一行代码:
是否正确? 应该是 bool operator() (const Message& lhs, const Message& rhs)
这段代码是关于Functor的教程示例代码。 可以在这里看到: http://www.cprogramming.com/tutorial/functors-function-objects-in-c++.html
谢谢