問題描述：

編寫一個程式計算兩個給定長方形的面積，其中在設計類成員函式addarea()（用於計算兩個長方形的總面積）時使用物件作為引數。

程式程式碼：

#include<iostream>
using namespace std;
class Rectangular
{
	public:
		Rectangular(double w,double l)
		{
			width = w;
			length = l;
		}
		double getc()
		{
			circumference = width + length;
			return circumference;
		}
		double adddata(Rectangular &r)
		{
			return (circumference + r.getc());
		}
	private:
		double width;
		double length;
		double circumference;	
}; 
int main()
{
	Rectangular r1(2.5,3.5);
	cout<<"Circumference of r1 ="<<r1.getc()<<endl; 
	Rectangular r2(2,3);
	cout<<"Circumference of r2 ="<<r2.getc()<<endl;
	cout<<"Circumference of r1+r2 ="<<r1.adddata(r2)<<endl;
	return 0; 	
} 
 

結果輸出：

Circumference of r1 =6
Circumference of r2 =5
Circumference of r1+r2 =11