请大家帮忙做些c++的题目，小弟不胜感谢

[jernymy]

一、 编写程序，输出ASCII码为32-127的字符。
二、 设计并测试一个名为Rectangle的矩形类，其属性（成员数据）为矩形的左下角与右上角两点的坐标。从键盘输入两点坐标，由主程序计算并输出矩形的面积。
三、 下面的程序有问题，请仔细体会使用指针时应避免出现的这个问题。
#include<iostream.h>
int main()
{
int *P;
*P=9;
cout<<”The value at P:”<<*P;
return 0;
}
四、 设有一个point类如下：
class point
{
private:
int X, Y；
public:
point(int xx=0, int yy=0){X=xx;Y=yy;}
int GetX(){return X;}
int GetY(){return Y;}
};
编程：声明一个指向该point类的对象的指针，并用该指针来完成对象的数据输入与输出。

五、 声明一个Shape基类，有存放数据的数据成员，接收数据的函数成员。在此基础上派生出Square（矩形）和Cirlce（圆）类，二者都有GetArea( )成员函数计算对象面积。使用这两个派生类各创建一个对象，并计算各对象面积。

[lijiawlm]

我晕 自己想
没一点技术含量~

[冷月清晖]

[Quote=引用 1 楼 lijiawlm 的回复:]
我晕 自己想
没一点技术含量~
[/Quote]

如：
1.

#include <stdio.h>

void main() 
{ 
	char c;
	for (int i=32;i<=127;i++)
	{
		c=i;
		printf("%c",c);
	}
}

[biosli]

又是作业题吧？
学习阶段还是自己做好...

[jernymy]

#include <iostream.h>

void main()
{
char c;
for (int i=32;i<=127;i++)
{
c=i;
cout("%c",c);
}
}

[jernymy]

二、 设计并测试一个名为Rectangle的矩形类，其属性（成员数据）为矩形的左下角与右上角两点的坐标。从键盘输入两点坐标，由主程序计算并输出矩形的面积。
这样写ok的吧？

struct point {
int x;
int y;
};

class rectangle {
public:
struct point a;
struct point b;

int GetArea() { return( b.y - a.y ) * ( b.x - a.x));}

};

[icansaymyabc]

作业题！20000日元，不讲价。

[icesnowjank]

#include <iostream>
#include <string>
#include <vector>
#include <map>
using namespace std;
class Shape
{
public:
	virtual void _draw()  = 0;
	virtual void _erase() = 0;
	virtual ~Shape(){cout<<"~Shape()"<<endl;}
};
class ShapeFactory
{
public:
	~ShapeFactory(){cout<<"~ShapeFactory()"<<endl;}
	friend class ShapeFactoryInitializer;
	class BadShapeCreation : public logic_error
	{
	public:
		BadShapeCreation(string _type)
			: logic_error("Can not create type:" + _type){}
	};
	static Shape* _CreateShape(const string& _id)
		throw(BadShapeCreation)
	{
		if (factories.find(_id) != factories.end())
			return factories[ _id ]->_Create();
		else
			throw BadShapeCreation(_id);
	}
private:
	virtual Shape* _Create() = 0;
	static  map<string,ShapeFactory*> factories;
};
map<string,ShapeFactory*> ShapeFactory::factories;
//////////////////////////////////////////////////////////////////////////
class Circle : public Shape
{
public:
	void _draw() {cout<<"Circle::_draw()" <<endl;}
	void _erase(){cout<<"Circle::_erase()"<<endl;}
	~Circle(){cout<<"Circle::~Circle()"<<endl;}
private:
	Circle(){}
	friend class ShapeFactoryInitializer;
	class  Factory;
	friend class Factory;
	class Factory : public ShapeFactory
	{
	public:
		Shape*  _Create(){return new Circle;}
		friend  class ShapeFactoryInitializer;
	};
};
//////////////////////////////////////////////////////////////////////////
class Square : public Shape
{
public:
	void _draw() {cout<<"Square::_draw()" <<endl;}
	void _erase(){cout<<"Square::_erase()"<<endl;}
	~Square(){cout<<"Square::~Square()"<<endl;}
private:
	Square(){}
	friend class ShapeFactoryInitializer;
	class Factory;
	friend class Factory;
	class Factory : public ShapeFactory
	{
	public:
		Shape* _Create(){return new Square;}
		friend class ShapeFactoryInitializer;
	};
};
class ShapeFactoryInitializer
{
private:
	static ShapeFactoryInitializer si;
	ShapeFactoryInitializer()
	{
		ShapeFactory::factories[ "Circle" ] = new Circle::Factory;
		ShapeFactory::factories[ "Square" ] = new Square::Factory;
	}
	~ShapeFactoryInitializer()
	{
		map<string,ShapeFactory*>::iterator it = ShapeFactory::factories.begin();
		while (it != ShapeFactory::factories.end())
			delete it ++->second;
	}
};
ShapeFactoryInitializer ShapeFactoryInitializer::si;
//////////////////////////////////////////////////////////////////////////
char* s[] = {"Circle","Square","Circle","Square","Square","Circle","Square","Circle","Square","Square"};
int _tmain(int argc, char* argv[])
{
	vector<Shape*> shapes;
	try
	{
		for (int i = 0;i < sizeof(s) / sizeof(s[ 0 ]);i ++)
			shapes.push_back(ShapeFactory::_CreateShape(s[ i ]));
	}
	catch (ShapeFactory::BadShapeCreation e)
	{
		cout<<e.what()<<endl;
		return EXIT_FAILURE;
	}
	for (int i = 0;i < shapes.size();i ++)
	{
		shapes[ i ]->_draw();
		shapes[ i ]->_erase();
	}
	for (vector<Shape*>::iterator _Pos = shapes.begin();_Pos != shapes.end();++ _Pos)
	{
		delete *_Pos;
		*_Pos = NULL;
	}
	system("PAUSE");
	return 0;
}

[jasonmike312]

声明一个Shape基类，有存放数据的数据成员，接收数据的函数成员。在此基础上派生出Square（矩形）和Cirlce（圆）类，二者都有GetArea( )成员函数计算对象面积。使用这两个派生类各创建一个对象，并计算各对象面积。
#include <iostream>
using namespace std;

class Shape
{//有存放数据的数据成员，接收数据的函数成员。不明白具体存放什么，没写。
public:
virtual void GetArea()=0;
};

class Square:public Shape
{
private:
double a;
double b;
public:
Square(double a,double b){this->a=a;this->b=b;};
void GetArea(){cout<<"矩形面积为："<<a*b;};
};

class Cirlce:public Shape
{
private:
double r;
public:
Cirlce(double r){this->r=r;};
void GetArea(){cout<<"圆形面积为："<<r*r*3.14;};
};

void main()
{
Shape *pShape[2];
pShape[0]=new Square(16.1,18.2);
pShape[1]=new Cirlce(3.0);
for(int i=0;i<2;i++)
{
pShape[i]->GetArea();
}
}

[morilasi]

太简单了，建议大家不要直接给答案了，老师留的作业自己做有好处

[sukyin]

[Quote=引用 6 楼 morilasi 的回复:]
太简单了，建议大家不要直接给答案了，老师留的作业自己做有好处
[/Quote]

[MagiSu]

题目简单大家就没有做的激情了。

[visame]

第3题：
#include <iostream.h>
int main()
{
int *P;//此处更改为int *p=new int;
*P=9;
cout < <”The value at P:” < <*P;
return 0;
} 

[kunpp]

5.#include<iostream.h>
class shape
{
protected:
double a,b;
public:
shape(double x){a=x;}
shape(double x,double y){a=x;b=y;}
virtual double mian()=0;
};

class chang:public shape
{public:
chang(double a,double b):shape(a,b)
{}
double mian()
{return a*b;}
};
class yuan:public shape
{

public:
yuan(double a):shape(a)
{}
double mian()
{return 3.14*a*a;}
};
void main()
{double a,b,m;
while(1)
{
cout<<"输入长方形的长，宽:";
cin>>a>>b;
chang c(a,b);
cout<<"长方形面积:"<<c.mian()<<endl;
cout<<"输入圆的半径：";
cin>>m;
yuan y(m);
cout<<"圆的面积"<<y.mian()<<endl;
}
}

[kunpp]

1.#include <iostream.h>
union pw
{
int i;
char ch[5];
};
void main()
{
pw a;
for(a.i=32;a.i<=127;a.i++)
cout<<a.ch<<" ";
}
4.#include<iostream.h>
class point
{
private:
int X,Y;
public:
point(int xx=0, int yy=0){X=xx;Y=yy;}
int GetX(){return X;}
int GetY(){return Y;}
};
void main()
{int c,d;
cin>>c>>d;
point a(c,d);
point (*b)=&a;
cout<<(*b).GetX()<<(*b).GetY()<<endl;
}