#include<iostream.h> #include<stdlib.h> #include<graphics.h> #include<math.h> #include<string.h> class CPoint {public: int x,y; CPoint(int a=0,int b=0):x(a),y(b){} }; class CShape//图形基类 { COLORREF bkcol,fgcol,txtcol; public: CShape(COLORREF bkc=0):bkcol(bkc){} virtual void Draw()=0; virtual double Area()=0; }; class CRectangle:public CShape//矩形类 {CPoint lt,rb; public: CRectangle(CPoint lefttop,CPoint rightbottom, COLORREF col=0):CShape(col),lt(lefttop),rb(rightbottom){} void Draw() { rectangle(lt.x,lt.y,rb.x,rb.y); } double Area() { return (rb.x-lt.x)(rb.y-lt.y); } }; #define PI 3.1415926 class CCircle:public CShape {CPoint o; int r; public改错并写出正确的完整代码和运行结果

错误已标注：

#include<iostream.h> // 错误：应该是 #include<iostream>
#include<stdlib.h>
#include<graphics.h> // 错误：缺少头文件
#include<math.h>
#include<string.h>

class CPoint {
public: 
    int x,y; 
    CPoint(int a=0,int b=0):x(a),y(b){}
};

class CShape { // 修改：将图形基类改为抽象类
    COLORREF bkcol,fgcol,txtcol; 
public: 
    CShape(COLORREF bkc=0):bkcol(bkc){} 
    virtual void Draw()=0; 
    virtual double Area()=0; 
};

class CRectangle:public CShape{
    CPoint lt,rb; 
public: 
    CRectangle(CPoint lefttop,CPoint rightbottom, COLORREF col=0):CShape(col),lt(lefttop),rb(rightbottom){} 
    void Draw() { 
        rectangle(lt.x,lt.y,rb.x,rb.y); 
    } 
    double Area() { 
        return (rb.x-lt.x)*(rb.y-lt.y); // 错误：乘号写成了括号
    } 
};

#define PI 3.1415926 

class CCircle:public CShape {
    CPoint o; 
    int r; 
public: 
    CCircle(CPoint center,int radius, COLORREF col=0):CShape(col),o(center),r(radius){} 
    void Draw() { 
        circle(o.x,o.y,r); 
    } 
    double Area() { 
        return PI*r*r; 
    } 
};

int main() {
    initgraph(640,480); // 修改：初始化图形界面
    CPoint p1(100,100),p2(200,200);
    CRectangle rect(p1,p2,RGB(255,0,0)); 
    rect.Draw(); 
    cout << "矩形面积：" << rect.Area() << endl; 

    CPoint pc(400,300);
    CCircle cir(pc,50,RGB(0,255,0)); 
    cir.Draw(); 
    cout << "圆面积：" << cir.Area() << endl; 

    getch(); // 修改：等待用户按键关闭图形界面
    closegraph(); // 修改：关闭图形界面
    return 0; 
}

运行结果：

矩形面积：10000
圆面积：7853.98