Posted on 2006-11-12 23:29
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C++學習資料
#include?<iostream>
using?namespace?std;
class?area?{
??double?dim1,?dim2;?
public:
??void?setarea(double?d1,?double?d2)
??{
????dim1?=?d1;
????dim2?=?d2;
??}
??void?getdim(double?&d1,?double?&d2)
??{
????d1?=?dim1;
????d2?=?dim2;
??}
??virtual?double?getarea()?=?0;?//?pure?virtual?function
};
class?rectangle?:?public?area?{
public:
??double?getarea()?
??{
????double?d1,?d2;
??
????getdim(d1,?d2);
????return?d1?*?d2;
??}
};
class?triangle?:?public?area?{
public:
??double?getarea()
??{
????double?d1,?d2;
??
????getdim(d1,?d2);
????return?0.5?*?d1?*?d2;
??}
};
int?main()
{
??area?*p;
??rectangle?r;
??triangle?t;
??r.setarea(3.3,?4.5);
??t.setarea(4.0,?5.0);
??p?=?&r;
??cout?<<?"Rectangle?has?area:?"?<<?p->getarea()?<<?'\n';
??p?=?&t;
??cout?<<?"Triangle?has?area:?"?<<?p->getarea()?<<?'\n';
??return?0;
}