调用存储在std映射中的成员函数指针

Question

我将地图存储在一个类中,该类具有字符串作为键和指向成员函数的指针作为值.我无法调用正确的函数抛出函数指针.这是代码:

#include <iostream>
#include <string>
#include <map>

using namespace std;


class Preprocessor;

typedef void (Preprocessor::*function)();



class Preprocessor
{

public:
    Preprocessor();
   ~Preprocessor();

   void processing(const string before_processing);

private:

   void   take_new_key();

   map<string, function>   srch_keys;

   string  after_processing;
};


Preprocessor::Preprocessor()
{
   srch_keys.insert(pair<string, function>(string("#define"), &Preprocessor::take_new_key));
}

Preprocessor::~Preprocessor()
{

}


void Preprocessor::processing(const string before_processing)
{
   map<string, function>::iterator result = srch_keys.find("#define");

   if(result != srch_keys.end())
      result->second; 
}


void Preprocessor::take_new_key()
{
   cout << "enters here";
}


int main()
{
   Preprocessor pre;
   pre.processing(string("...word #define other word"));

   return 0;
}

在函数中,Preprocessor::processing如果在地图中找到字符串,那么我调用正确的函数.问题是,在这段代码中,Preprocessor::take_new_key永远不会被调用.

哪里出错了？

谢谢

Answer 1

正确的语法是这样的:

(this->*(result->second))();

那很难看.所以试试吧:

auto mem = result->second;  //C++11 only
(this->*mem)();

使用哪个让你开心.