大家帮我看看这个程序有什么问题!谢谢了.

[shuirh]

#include <iostream.h>
static const pai = 3.1415926;

class Shape
{
public:
virtual float GetArea() = 0;
virtual float GetPerim() = 0;
};

class Rectangle : public Shape
{
float lenth;
float width;
public:
Rectanlge(float len, float wid);
float GetArea();
float GetPerim();
};

class Circle : public Shape
{
float radius;
public:
Circle(float r = 0);
float GetArea();
float GetPerim();
};

float Shape :: GetArea()
{
cout << "the area of Shape is:";
}

float Shape :: GetPerim()
{
cout << "the perim of Shape is:";
}

//这个构造函数有什么问题?
Rectangle :: Rectangle(float len, float wid)
{
lenth = len;
width = width;
}

float Rectangle :: GetArea()
{
cout << "the area of Rectangle is:";
return lenth * width;
}

float Rectangle :: GetPerim()
{
cout << "the perim of Rectangle is:";
return 2 * (lenth + width);
}

Circle :: Circle(float r)
{
radius = r;
}

float Circle :: GetArea()
{
cout << "the area of Circle is:";
return pai * radius * radius;
}

float Circle :: GetPerim()
{
cout << "the perim of Circle is:";
return 2 * pai * radius;
}

void fun(Shape *point)
{
point->GetArea;
point->GetPerim;
}

main()
{
Shape *point = new Shape; //这句报错

fun(point);

Rectangle rec(4, 5); //这句也报错

point = &rec;
fun(point);

Circle cir(10);
point = ○
fun(point);
}

大家帮我看看这3个地方如何修改啊?小弟我不胜感激了啊!

[lw1a2]

#include <iostream>
using namespace std;

static const double pai = 3.1415926;

class Shape
{
public:
virtual double GetArea() = 0;
virtual double GetPerim() = 0;
};

class Rectangle : public Shape
{
double lenth;
double width;
public:
Rectangle(double len, double wid);
double GetArea();
double GetPerim();
};

class Circle : public Shape
{
double radius;
public:
Circle(double r = 0);
double GetArea();
double GetPerim();
};

//double Shape :: GetArea()
//{
// cout << "the area of Shape is:";
//
//}
//
//double Shape :: GetPerim()
//{
// cout << "the perim of Shape is:";
//}

//这个构造函数有什么问题?
Rectangle :: Rectangle(double len, double wid)
{
lenth = len;
width = width;
}

double Rectangle :: GetArea()
{
cout << "the area of Rectangle is:";
return lenth * width;
}

double Rectangle :: GetPerim()
{
cout << "the perim of Rectangle is:";
return 2 * (lenth + width);
}

Circle :: Circle(double r)
{
radius = r;
}

double Circle :: GetArea()
{
cout << "the area of Circle is:";
return pai * radius * radius;
}

double Circle :: GetPerim()
{
cout << "the perim of Circle is:";
return 2 * pai * radius;
}

void fun(Shape *point)
{
point->GetArea();
point->GetPerim();
}

main()
{
//Shape *point = new Shape; //不能创建纯虚类

//fun(point);

Rectangle rec(4, 5); //这句也报错

Shape *point = &rec;
fun(point);

Circle cir(10);
point = ○
fun(point);
}

错太多了，都不想改了，照书抄麻烦多对两遍

[lightnut]

1.
class Rectangle : public Shape
{
.....
Rectanlge(float len, float wid); //这个构造函数写错了: xxxxxglx不是xxxxxlgx
.....
}
2.
class Shape
{
public:
virtual float GetArea() = 0;
.....
}
这里=0表示Shape是个抽象基类, 不能创建其对象, 所以
Shape *point = new Shape
会报错!

[yangch_nhcmo]

改了一下,LZ再看看

#include <iostream.h>
using namespace std;
static const int pai = 3.1415926; //要注明类型

class Shape
  {
  public:
    virtual float GetArea() = 0;
    virtual float GetPerim() = 0;
  };

class Rectangle : public Shape
  {
    float lenth;
    float width;
  public:
    //Rectanlge(float len, float wid); //这里打错了,导致下面调用函数时出错;
    Rectangle(float len, float wid);
    float GetArea();
    float GetPerim();
  };

class Circle : public Shape
  {
    float radius;
  public:
    Circle(float r = 0);
    float GetArea();
    float GetPerim();
  };

float Shape :: GetArea()
{
  cout << "the area of Shape is:";
}

float Shape :: GetPerim()
{
  cout << "the perim of Shape is:";
}

//这个构造函数有什么问题? //因为上面打错字母,找不到函数出错
Rectangle :: Rectangle(float len, float wid)
{
  lenth = len;
  width = width;
}

float Rectangle :: GetArea()
{
  cout << "the area of Rectangle is:";
  return lenth * width;
}

float Rectangle :: GetPerim()
{
  cout << "the perim of Rectangle is:";
  return 2 * (lenth + width);
}

Circle :: Circle(float r)
{
  radius = r;
}

float Circle :: GetArea()
{
  cout << "the area of Circle is:";
  return pai * radius * radius;
}

float Circle :: GetPerim()
{
  cout << "the perim of Circle is:";
  return 2 * pai * radius;
}

void fun(Shape *point)
{
  point->GetArea(); //point->GetArea ==> point->GetArea()
  point->GetPerim(); //point->GetPerim ==>point->GetPerim()
}

int main()
{
// Shape* point = new Shape;    //Shape 是个抽象类,不能分配空间
  Shape *point;

  point = new Circle;

  fun(point);

  Rectangle rec(4, 5);

  point = &rec;
  fun(point);

  Circle cir(10);
  point = ○
  fun(point);
}

[waizqfor]

错误不少啊 LZ再好好对对书

#include <iostream.h> 
static const double pai = 3.1415926; 

class Shape 
{ 
public: 
virtual float GetArea() = 0; 
virtual float GetPerim() = 0; 
}; 

class Rectangle : public Shape 
{ 
float lenth; 
float width; 
public: 
Rectangle(float len, float wid); 
float GetArea(); 
float GetPerim(); 
}; 

class Circle : public Shape 
{ 
float radius; 
public: 
Circle(float r = 0); 
float GetArea(); 
float GetPerim(); 
}; 

float Shape :: GetArea() 
{ 
cout << "the area of Shape is:"; 
} 

float Shape :: GetPerim() 
{ 
cout << "the perim of Shape is:"; 
} 

//这个构造函数有什么问题? 
Rectangle :: Rectangle(float len, float wid) 
{ 
lenth = len; 
width = width; 
} 

float Rectangle :: GetArea() 
{ 
cout << "the area of Rectangle is:"; 
return lenth * width; 
} 

float Rectangle :: GetPerim() 
{ 
cout << "the perim of Rectangle is:"; 
return 2 * (lenth + width); 
} 

Circle :: Circle(float r) 
{ 
radius = r; 
} 

float Circle :: GetArea() 
{ 
cout << "the area of Circle is:"; 
return pai * radius * radius; 
} 

float Circle :: GetPerim() 
{ 
cout << "the perim of Circle is:"; 
return 2 * pai * radius; 
} 

void fun(Shape *point) 
{ 
point->GetArea; //调用的形式错了
point->GetPerim; 
} 

main() 
{ 
//Shape *point = new Shape;    //这句报错 
Shape *point;
fun(point); 

Rectangle rec(4, 5);    //这句也报错 

point = &rec; 
fun(point); 

Circle cir(10); 
point = ○ 
fun(point); 
} 

[lq651659889]

你的是不是少了using namespace std;啊！要不你也要这样输出撒std::cout.

[shuirh]

/*8-9 定义一个Shape抽象类，在此基础上派生出Rectangle和Circle，
*二者都有GetArea()函数计算对象的面积，GetPerim()函数计算对象的周长。
*/

#include <iostream.h>
static const pai = 3.1415926;

class Shape
{
public:
//基类的纯虚函数可以只声明不定义吗? //纯虚函数本来就只声明不定义
Shape()
{
cout << "Shape constructing" << endl;
}
virtual float GetArea() = 0;
virtual float GetPerim() = 0;
};

class Rectangle : public Shape
{
float lenth;
float width;
public:
Rectangle(float len, float wid)
{
lenth = len;
width = wid;
}
float GetArea();
float GetPerim();
};

class Circle : public Shape
{
float radius;
public:
Circle(float r = 0);
float GetArea();
float GetPerim();
};

/*float Shape :: GetArea()
{
cout << "the area of Shape is:";
return -1;
}

float Shape :: GetPerim()
{
cout << "the perim of Shape is:";
return -1;
}*/

float Rectangle :: GetArea()
{
cout << "the area of Rectangle is:";
return lenth * width;
}

float Rectangle :: GetPerim()
{
cout << "the perim of Rectangle is:";
return 2 * (lenth + width);
}

Circle :: Circle(float r)
{
radius = r;
}

float Circle :: GetArea()
{
cout << "the area of Circle is:";
return pai * radius * radius;
}

float Circle :: GetPerim()
{
cout << "the perim of Circle is:";
return 2 * pai * radius;
}

void fun(Shape *point)
{
cout << point->GetArea() << endl;
cout << point->GetPerim() << endl;
}

main()
{
//Shape *point = new Shape; //Shape是一个抽象类,抽象类不能定义对象,不能分配内存空间
Shape *point_ = NULL;
Rectangle rec(4, 5);
Circle cir(10);

//fun(point_);

point_ = &rec;
fun(point_);

point_ = ○
fun(point_);

//delete point;
}

终于改对了.
我真的很差啊,我都不好意思发帖了.
但是大家很热情啊,对我的帮助非常大,谢谢你们了.