c++引用，函数重载

#include <iostream>
using namespace std;

class Rect
{
private:
    int w;
    int h;
public:
    void init(int n1,int n2);
    int set_w();
    int set_h();
    void show();
};
void Rect::init(int n1, int n2)
{
    w = n1;
    h = n2;
}
int Rect::set_w()
{
    return w;
}
int Rect::set_h()
{
    return h;
}
void Rect::show()
{
    cout << "周长:" << (h+w)*2 << endl;
    cout << "面积:" << w*h << endl;
}

void show(Rect r1)
{
    cout << "周长:" << (r1.set_h()+r1.set_w())*2 << endl;
    cout << "面积:" << r1.set_w()*r1.set_h() << endl;
}
int main()
{
    Rect r1;
    r1.init(5,12);
    r1.show();
    return 0;
}