调用存储在标准映射中的成员函数指针 [英] Calling a member function pointer stored in a std map
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问题描述
我将地图存储在一个类中,该类具有字符串作为键,而指向成员函数的指针作为值.我在调用正确的函数时遇到了麻烦,即抛出了函数指针. 这是代码:
I'm storing a map in a class that has strings as keys and pointers to member functions as values. I'm having trouble calling the right function throw the function pointer. Here is the code:
#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Preprocessor::processing
中,如果在映射中找到该字符串,则调用适当的函数.问题在于,在此代码中,从未调用Preprocessor::take_new_key
.
In function Preprocessor::processing
if the string is found in the map then, I call the proper function. The problem is that, in this code, Preprocessor::take_new_key
is never called.
错误在哪里?
谢谢
推荐答案
正确的语法是这样的:
(this->*(result->second))();
那太丑了.因此,让我们尝试一下:
That is ugly. So lets try this:
auto mem = result->second; //C++11 only
(this->*mem)();
使用使您感到快乐的任何方式.
Use whichever makes you happy.
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