Inheritance Dalam C++

Posting untuk praktikum tanggal 11 oktober 2010, yang isisnya tentang inheritance / pewarisan dalam c++.

#include <cstdlib>
#include <iostream>

using namespace std;
class Bilangan{
friend ostream& operator<<(ostream&, const Bilangan&);
friend istream& operator>>(istream&, Bilangan&);
public:
Bilangan(int a0=0,float b0=0.0):a(a0),b(b0){}
void banding_int(const Bilangan&, const Bilangan&);
Bilangan& operator=(const Bilangan&);
Bilangan operator+(const Bilangan&)const;
Bilangan operator-()const;
protected:
int a;
float b;
};

ostream& operator<<(ostream& out, const Bilangan& x)
{
out<<“Bagian integer: “<<x.a<<endl;
out<<“Bagian float : “<<x.b<<endl;
return out;
}
void Bilangan::banding_int(const Bilangan&x, const Bilangan& y)
{
if(x.a>y.a)cout<<x.a<<“::x lebih besar dari”<<y.a<<“::y”;
else cout<<x.a<<“::x lebih kecil dari”<<y.a<<“::y”;
}

Bilangan& Bilangan::operator=(const Bilangan& x)
{
a=x.a;
b=x.b;
return *this;
}

istream& operator>>(istream& in, Bilangan& x)
{
cout<<“\nMasuk bagian integer:”;
in>>x.a;
cout<<“Masuk bagian float :”;
in>>x.b;
return in;
}

Bilangan Bilangan::operator+(const Bilangan& x)const
{Bilangan cc;
cc.a=a+x.a;
cc.b=b+x.b;
return cc;
}

Bilangan Bilangan::operator-()const
{Bilangan x;
x.a=-a;
x.b=-b;
return x;
}
//
class Bil_char:public Bilangan {
friend ostream& operator << (ostream&, const Bil_char&);
public:
Bil_char(int a0=0, int b0=0, char ch=’x’):Bilangan(a0,b0),c(ch){}
private:
char c;
};
ostream& operator <<(ostream& out, const Bil_char& x){
out<<“bagian INteger : “<<x.a<<endl;
out<<“bagian float : “<<x.b<<endl;
out<<“bagian Char : “<<x.c<<endl;
return out;
}

int main(){
Bilangan s,t(-2,3.14),d;
cout<<“Nilai awal s\n”<<s;
cout<<“Nilai awal t dari deklarasi\n”<<t;
s=t;
cout<<“Setelah s di-assign t\n”;
cout<<“Nilai s\n”<<s;
cout<<“masukan nilai-nilai object d”;
cin>>d;
cout<<“setelah d+t=> \n”<<d+t;
cout<<“Nilai d dinegatifkan\n”<<-d;

system(“PAUSE”);
return EXIT_SUCCESS;
}