函数指针堆栈：如何调用函数？

Question

我有一堆函数指针（都是 void 类型且没有参数）。我很难找出如何调用/执行堆栈中的函数？

如果你看一下下面的简单例子，一切都会编译&除了最后一行之外都有效

typedef class InstructionScreen;
typedef void (InstructionScreen::*MemberFuncPtr)();
stack <MemberFuncPtr> instructionStep;              // This is how I declare it. Works
instructionStep.push( &InstructionScreen::step1 );  // This is how I add the member function step(). Works
(*instructionStep.top())();                         // How do I call the function now? This doesn't work

这是我试图编译的整个代码：

class InstructionScreen
{
     public:
         InstructionScreen()
         {
              instructionStep.push( &InstructionScreen::step1 );
              instructionStep.push( &InstructionScreen::step2 );   

              // add timer to call run instructions each 10 seconds        
         }

         void step1()
         {
         }

         void step2()
         {
         }

         void runInstructions()
         {
              if ( !instructionStep.empty() )
              {
                  *(instructionStep.top())(); 
                  instructionStep.pop();
              }
              // else kill timer
         }

     private:
          stack <MemberFuncPtr> instructionStep;   
};

Answer 1

您需要一个实例来调用成员函数。试试这个：

InstructionScreen screen;
MemberFuncPtr step = instructionStep.top();
(screen.*step)();

要从另一个成员函数中运行堆栈中的函数，您可以使用：

MemberFuncPtr step = instructionStep.top();
(this->*step)();