帮忙看看这个程序怎么修改？

#include <iostream.h>
class Animal

void Setvalue(Animal &int);
void Setvalue(Animal&,int,int);

class Animal
{
public:
friend void setvalue(Animal&,int);
protected:
int itsweight;
int itsage;
};
void Setvalue(Animal& ta,int tw)
{
ta.itsweight=tw;
}
void Setvalue(Animal& ta,int tw,int tn)
{
ta.itsweight=tw;
ta.itsage=tn;
}
int main()
{
Animal peppy;
Setvalue(peppy,5);
Setvalue(peppy,7,9);
return 0;
}

C/C++ code

#include <iostream.h>
class Animal;

void Setvalue(Animal&,int,int);

class Animal
{
public:
    friend void setvalue(Animal&,int);
    void setWeight( int w)
    {
        itsweight = w;
    }
    void setAge( int a)
    {
        itsage = a;
    }
protected:
    int itsweight;
    int itsage;
};
void Setvalue(Animal& ta,int tw)
{
    ta.setWeight(tw);
}
void Setvalue(Animal& ta,int tw,int tn)//非友元函数不能直接调用protected成员
{
    ta.setWeight(tw);
    ta.setAge(tn);
}
int main()
{
    Animal peppy;
    Setvalue(peppy,5);
    Setvalue(peppy,7,9);
    return 0;
}