函数指针

int fun(int a, int b)
{
return a+b;
}
int main()
{
int(*fp1)(int, int)   = fun;
cout<<fp1(1,2)<<endl;


typedef int(*Fp2)(int, int);
Fp2 fp2 = fun;
cout<<fp2(1,2)<<endl;
//////////////////////////////////////////////////////////////////////////

std::function<int(int, int)>fp3 = fun;
cout<<fp3(2,4)<<endl;


typedef std::function<int (int, int)>Fp3;
Fp3 fp3 = fun;
cout<<fp3(1,2)<<endl;
//////////////////////////////////////////////////////////////////////////

std::function<int(int, int)>fp4 =  std::bind(fun,std::placeholders::_1,std::placeholders::_2);
cout<<fp4(1,2)<<endl;


typedef std::function<int(int, int)>Fp4;
Fp4 fp4 = std::bind(fun,std::placeholders::_1,std::placeholders::_2);
cout<<fp4(1,2)<<endl;


return 0;
}