假设我有一个带有一些简单函数指针的简单类,就像这样:
class ClassWithFuncPointer
{
public:
inline void firstFunction() { /* do something */ };
inline void secondFunction() { /* do something */ };
// MY FUNCTION POINTER
void (ClassWithFuncPointer::*funcPointer) ();
// AND I CAN DEFINE IT BY DEFAULT IN CONSTRUCTOR LIKE THAT:
ClassWithFuncPointer()
{
funcPointer = &ClassWithFuncPointer::firstFunction;
}
// AND NOW I CAN USE MY FUNCTION POINTER INSIDE OF ClassWithFuncPointer, LIKE THAT:
void useFunctionPointer()
{
(this->*funcPointer )();
}
}
所以(this->*funcPointer )();
在这里完成工作。
但是我无法弄清楚如何在其他课程中使用我的funcPointer
,我的意思是这样的:
class otherClass
{
otherClass(){};
ClassWithFuncPointer instanceOfClassWithFuncPointer;
}
现在如何在funcPointer
成员的otherClass
内使用instanceOfClassWithFuncPointer
。可能吗?
我尝试了许多变体:
(this->*instanceOfClassWithFuncPointer.funcPointer)();
或
(instanceOfClassWithFuncPointer.*funcPointer)();
或
( (&instanceOfClassWithFuncPointer)->*funcPointer )();
或者只是
instanceOfClassWithFuncPointer.funcPointer();
但总是会出错。我不知道。
答案 0 :(得分:0)
以下(仅限C ++ 11或更高版本)呢?
auto fp = instanceOfClassWithFuncPointer.funcPointer;
(instanceOfClassWithFuncPointer.*fp)();
还是(与C ++ 98兼容,也许使用较短的变量名)?
(instanceOfClassWithFuncPointer.*instanceOfClassWithFuncPointer.funcPointer)();
以下是一个完整的工作示例
#include <iostream>
struct ClassWithFuncPointer
{
public:
inline void firstFunction ()
{ std::cout << "cwfp::firstFunction()" << std::endl; }
inline void secondFunction ()
{ std::cout << "cwfp::secondFunction()" << std::endl; }
void (ClassWithFuncPointer::*funcPointer) ();
ClassWithFuncPointer()
{ funcPointer = &ClassWithFuncPointer::firstFunction; }
void useFunctionPointer()
{ (this->*funcPointer )(); }
};
class otherClass
{
public:
otherClass ()
{ }
ClassWithFuncPointer instanceOfClassWithFuncPointer;
void foo ()
{
auto fp = instanceOfClassWithFuncPointer.funcPointer;
(instanceOfClassWithFuncPointer.*fp)();
}
};
int main ()
{
otherClass oc;
oc.foo();
}