. 以下程序能根据对象提供的长方形的长和宽得到该长方形的面积和周长 class rectangle { private: float ledge,sedge public: rectangle(){ledge=0;sedge=0;} rectangle(float a,float b) {ledge=a; sedge=b;} void area(){cout<<”面积:”<< ▁▁▁ << endl;} void length(){cout<<”周长:”<< ▁▁▁ << endl;} }; void main() { rectangle A(3.5, 2.0),B(4.2, 2.0); A.area(); A.length(); B.area(); B.length(); }

答案：

class rectangle {
private:
float ledge, sedge;
public:
rectangle() {
ledge = 0;
sedge = 0;
}
rectangle(float a, float b) {
ledge = a;
sedge = b;
}
void area() {
cout << "面积:" << ledge * sedge << endl;
}
void length() {
cout << "周长:" << 2 * (ledge + sedge) << endl;
}
};

void main() {
rectangle A(3.5, 2.0), B(4.2, 2.0);
A.area();
A.length();
B.area();
B.length();
}