#include 
    
     int add(int a,int b){	return a+b;}struct Obj{  int operator()(int a,int b)  {	return a+b;  }};class OperatingNumbers{private:	int num1;	int num2;public:	explicit OperatingNumbers(int a=1,int b=1):num1(a),num2(b){}	~OperatingNumbers(){}public:	int getNumbyRtnFunction(int (*p)(int a,int b))	{		return p(num1,num2);  //利用回调函数来求和	}	int getNumbyObj(Obj obj)	{		return obj(num1,num2);  //利用函数对象，即仿函数来求和	}	int getNumbyLambda()	{		return [](int a,int b)->int{ return a+b;}(num1,num2); //利用lambda表达式求和	}};int main(int argc, char* argv[]){	OperatingNumbers oNum(2,3);	Obj o;	std::cout<
     
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