已知一个全局函数printArea(arg),其中，arg为某一种平面图形，该函数的作用是打印参数arg所表示图形的面积。先假设，只存在正方形、圆形、正三角形三种平面图形。使用继承的方式，设计相关的类，并实现该全局函数的功能。
提示：设计基类Shape，设计派生类Square，Circle，Triangle
这是代码有不适当的地方请大家提出来，谢谢
#include
#include
using namespace std;
class Shape
{
public:
virtual double area() = 0;
};
class Circle :public Shape
{
public:
Circle(int radius){
this->radius = radius;
}
virtual double area(){
return 3.14*radius*radius;
}
private:
int radius;
};
class Square :public Shape
{
public:
Square(int rim){
this->rim = rim;
}
virtual double area(){
return rim*rim;
}
private:
int rim;
};
class Triangl :public Shape
{
public:
Triangl(double rim){
this->rim = rim;
}
virtual double area(){
double i = rim*rim;
double j = (rim/2)*(rim/2);
double hige = sqrt(i - j);
return rim*hige/2;
}
private:
double rim;
};
void printArea(Shape *arg)
{
cout << arg->area() << endl;
}
int main(int argc, char* argv[])
{
Shape *squ = new Square(2);
Shape *cir = new Circle(2);
Shape *tri = new Triangl(5);
printArea(squ);
printArea(cir);
printArea(tri);
delete squ;
delete cir;
delete tri;
return 0;
}
求代码，谢谢了，函数真的是不会。
全局函数只是起个调用相关图形的计算面积打印结果的作用，他的参数就是定义为基类类型，运行时再动态判断，使用继承是让你实现 多态的技术，基类可以直接就写个虚方法计算面积，然后子类继承基类实现基类的虚方法就可以了
#include
#include
#define P (3.14)
using namespace std;
class Shape
{
public:
virtual double area() = 0;
double side;
};
class Circle :public Shape
{
public:
Circle(double side){
this->side = side;
}
virtual double area(){
return P*side*side;
}
};
class Square :public Shape
{
public:
Square(double side){
this->side = side;
}
virtual double area(){
return side*side;
}
};
class Triangl :public Shape
{
public:
Triangl(double side){
this->side = side;
}
virtual double area(){
double i = side*side;
double j = (side/2)*(side/2);
double hige = sqrt(i - j);
return side*hige/2;
}
};
void printArea(Shape *arg)
{
cout << arg->area() << endl;
}
int main(int argc, char* argv[])
{
Shape *squ = new Square(2);
Shape *cir = new Circle(2);
Shape *tri = new Triangl(5);
printArea(squ);
printArea(cir);
printArea(tri);
delete squ;
delete cir;
delete tri;
return 0;
}