54 lines
1.3 KiB
C++
54 lines
1.3 KiB
C++
#include <iostream>
|
|
#include <tr1/memory>
|
|
using std::tr1::shared_ptr;
|
|
using std::tr1::enable_shared_from_this;
|
|
|
|
struct Arg {
|
|
virtual int run() = 0;
|
|
virtual ~Arg() { };
|
|
};
|
|
|
|
int A(int, shared_ptr<Arg>, shared_ptr<Arg>, shared_ptr<Arg>,
|
|
shared_ptr<Arg>, shared_ptr<Arg>);
|
|
|
|
class B : public Arg, public enable_shared_from_this<B> {
|
|
private:
|
|
int k;
|
|
const shared_ptr<Arg> x1, x2, x3, x4;
|
|
|
|
public:
|
|
B(int _k, shared_ptr<Arg> _x1, shared_ptr<Arg> _x2, shared_ptr<Arg> _x3,
|
|
shared_ptr<Arg> _x4)
|
|
: k(_k), x1(_x1), x2(_x2), x3(_x3), x4(_x4) { }
|
|
int run() {
|
|
return A(--k, shared_from_this(), x1, x2, x3, x4);
|
|
}
|
|
};
|
|
|
|
class Const : public Arg {
|
|
private:
|
|
const int x;
|
|
public:
|
|
Const(int _x) : x(_x) { }
|
|
int run () { return x; }
|
|
};
|
|
|
|
int A(int k, shared_ptr<Arg> x1, shared_ptr<Arg> x2, shared_ptr<Arg> x3,
|
|
shared_ptr<Arg> x4, shared_ptr<Arg> x5) {
|
|
if (k <= 0)
|
|
return x4->run() + x5->run();
|
|
else {
|
|
shared_ptr<Arg> b(new B(k, x1, x2, x3, x4));
|
|
return b->run();
|
|
}
|
|
}
|
|
|
|
int main() {
|
|
std::cout << A(10, shared_ptr<Arg>(new Const(1)),
|
|
shared_ptr<Arg>(new Const(-1)),
|
|
shared_ptr<Arg>(new Const(-1)),
|
|
shared_ptr<Arg>(new Const(1)),
|
|
shared_ptr<Arg>(new Const(0))) << std::endl;
|
|
return 0;
|
|
}
|