c++基础题

例题2-1
#include "stdafx.h"
#include"iostream"

int fun(int a,int b)
{
	int c;
	c=a+b;
	return c;
}

int _tmain(int argc, _TCHAR* argv[])
{
	int a,b,c;
	std::cout<<"请输入两个整数:";
	std::cin>>a>>b;
	c=fun(a,b);
	std::cout<<"the sum of a and b is"<<c;


	return 0;
}

例题2-2

#include "stdafx.h"
#include"iostream"
using namespace std;
int main()
{
	const double pi=3.14159;
	double s=0;
	s=pi*4.0*4.0;
	cout<<s<<endl;
	return 0;
}
例题2-3
//用数组来处理菲欧娜博数列问题
#include "stdafx.h"
#include"iostream"
#include"iomanip"//设置域宽函数
using namespace std;
int main()
{
	int i;
	int f[20]={1,1};
	for(i=2;i<20;i++)
	f[i]=f[i-2]+f[i-1];
	for(i=0;i<20;i++)
	{if(i%5==0)
	cout<<endl;
	cout<<setw(8)<<f[i];
	}
	cout<<endl;
	return 0;
}
例2-4

//将一个二维数组行和列互换，存到另一个二维数组中。
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
	int a[2][3]={{1,2,3},{4,5,6}};
	int b[3][2],i,j;
   cout<<"array a:"<<endl;
   for(i=0;i<=1;i++)
   {
	   for(j=0;j<=2;j++)
	   {
		   cout<<a[i][j]<<" ";
		   b[j][i]=a[i][j];
	   }
	   cout<<endl;
   }
   cout<<"array b"<<endl;
   for(i=0;i<=2;i++)
   {
	   for(j=0;j<=1;j++)
		   cout<<b[i][j]<<" ";
	   cout<<endl;
   }


	return 0;
}
例2-5
//输入三个字符串，要求将字母按从小到大的顺序输出。
#include "stdafx.h"
#include"iostream"
#include"string"

using namespace std;
int main()
{
	string string1,string2,string3,temp;
	cout<<"please input three strings:";
	cin>>string1>>string2>>string3;
	if(string1>string3)
	{
		temp=string2;
		string2=string3;
		string3=temp;
	}
	if(string1<=string2)
	cout<<string1<<" "<<string2<<" "<<string3<<endl;
	else if(string1<=string3)
		cout<<string2<<" "<<string1<<" "<<string3<<endl;
	else cout<<string2<<" "<<string3<<" "<<string1<<endl;


	return 0;
}
例2-6
//引用参数分析
#include "stdafx.h"
#include"iostream"


using namespace std;
int main()
{
	void swa(int &p1,int &p2);
	int a,b;
	cout<<"input two numbles:";
	cin>>a>>b;
	swap(a,b);
	cout<<a<<' '<<b;


	return 0;
}
void swap(int &p1,int &p2)
{
	int p;
	p=p1;
	p1=p2;
	p2=p;
}
例3-1
//判断用户的输入，如果用户输入的大于0，则屏幕上显示“正数”
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
	int a;
	cin>>a;
	if(a>0) cout<<"正数"<<endl;


	return 0;
}
例3-2
//判断键盘输入的整数是否为偶数，是输出yes，不是输出no
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
	int x;
	cout<<"请输入一个整数：\n";
	cin>>x;
	if(x%2==0)
		cout<<"yes"<<endl;
	else cout <<"no"<<endl;

	return 0;
}
例3-3
//计算分段函数
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
	float x,y;
		cout<<"请输入x的值";
			cin>>x;
			if(x==10)
				cout<<"not define x."<<endl;
			else {if(x<=1) y=x+5;
			else if (x<10) y=2*x;
			else y=3/(x-10);
			cout <<"x= "<<x<<"y= "<<y;
		        	}

	return 0;
}
例3-4
//求一元二次方程的根。系数由键盘输入；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
	float a,b,c;
	float delta,x1,x2;
	cout<<"please input three numbles a(a!=0),b,c:"<<endl;
	cin>>a>>b>>c;
		delta=b*b-4*a*c;
		if(delta>=0)
			if(delta>0)
			{
				delta=sqrt(delta);
				x1=(-b+delta)/(2*a);
				x2=(-b-delta)/(2*a);
				cout<<"have two deffierent :";
				cout<<"x1="<<x1<<'\t'<<"x2="<<x2<<endl;
			}
			else 
			{
				cout<<"have two same  solutions:";
				cout<<"x1=x2="<<-b/(2*a)<<endl;
			}
		else cout<<"no solution"<<endl;

	return 0;
}
例3-5
//将学生成绩转化为等级；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
int score;
cout<<"please input the score of  student:"<<endl;
cin>>score;
if(score>100||score<0)
	cout<<"input warnning"<<endl;
else switch(score/10)
{
case 10:
	case 9:cout<<"A lever"<<endl;break;
		case 8:cout<<"B lever"<<endl;break;
			case 7:cout<<"C lever"<<endl;break;
				case 6:cout<<"E lever"<<endl;break;
default:cout<<"E lever"<<endl;
}
					
}
例3-6
//求使s=1+1/2+1/3+...+1/n的值大于10的n的最小值；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
float sum=0;
int n=1;
while(sum<10)
{
	sum=sum+1.0/n;
	n++;
}
cout<<"sum="<<sum<<endl;
cout<<"n="<<n<<endl;
return 0;					
}
3-7
//输出1-100的奇数，并求解其和；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
int n=1,sum=0;
do
{
	if(n%2!=0)
	{
		cout<<n<<"\t";
		sum=sum+n;
	}
	n++;
}
while(n<=100);
cout<<"sum="<<sum<<endl;
return 0;
}
例3-8
//能被1，2，4，8整除的，这些数称作为8的因子，请列举48的所有因子，并列出所有因子之和；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
int sum=0,t;
cout<<"48的所有因子为："<<endl;
for(int i=1;i<=48;i++)
{
	if(48%i==0)
	{
		t=i;
		sum+=t;
		cout<<t<<"\t";
	}
}
cout<<"48的所有因子之和为："<<sum<<endl;

return 0;
}
例3-9
//利用for语句嵌套打印乘法表；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
int fac=1;
cout<<"\n 乘法表"<<endl;
for(int i=1;i<10;i++)
	cout<<"\t"<<i;
cout<<endl<<"----------------------------------------------------------------------------"<<endl;
for(int i=1;i<10;i++)
{
	cout<<i<<"|";
	for(int j=1;j<10;j++)
	{
		fac=i*j;
		cout<<"\t"<<fac;
	}
	cout<<endl;
}

return 0;
}
例3-10
//利用goto语句计算1-100的累加和；
#include "stdafx.h"
#include"iostream"

using namespace std;
int main()
{
int i=1;
int sum=0;
loop:
if(i<=100)
{
	sum+=i;
	i++;
	goto loop;
}
cout<<"1-100的累加和为："<<sum<<endl;


return 0;
}

例4-1
//单向传值实例；
#include "stdafx.h"
#include"iostream"

using namespace std;

void swap(int x,int y)
{
	int z;
	z=x;
	x=y;
	y=z;
	cout<<"the x,y is:"<<x<<" "<<y<<endl;
}
int main()
{
int m,n;
cin>>m>>n;
swap(m,n);
cout<<"the m,n is"<<m<<" "<<n;


return 0;
}

例4-2
//传递地址实例；
#include "stdafx.h"
#include"iostream"

using namespace std;

void fun(int a[2])
{
	for(int i=0;i<2;i++)
		a[i]=a[i]+2;

}
int main()
{
	int b[2]={2,4};
	cout<<b[0]<<'\t'<<b[1]<<endl;
	fun(b);
	cout<<b[0]<<"\t"<<b[1]<<endl;

return 0;
}
例4-3
//传递引用实例；
#include "stdafx.h"
#include"iostream"

using namespace std;

void swap(int &x,int&y)
{
	int z;
	z=x;
	x=y;
	y=z;
	cout<<"x="<<x<<"\t"<<"y="<<y<<endl;


}
int main()
{
	int m,n;
	cin>>m>>n;
	swap(m,n);
	cout<<"m="<<m<<"\t"<<"n="<<n<<endl;

return 0;
}
例4-4
//函数返回值实例；
#include "stdafx.h"
#include"iostream"

using namespace std;
int max(int x,int y)
{
	int z;
	z=x>y?x:y;
	return z;}
int main()
{
	int m,n,z;
	cout<<"please input two numbles"<<endl;
	cin>>m>>n;
	z=max(m,n);
	cout<<"the max of m,n is"<<z;

return 0;
}
例4-5
//利用弦截法求解方程f(x)=x^3-5x^2+16x-80=0的根；
#include "stdafx.h"
#include"iostream"

using namespace std;
double f(double);
double xpoint(double,double);
double root(double,double);

int main()
{
	double x1,x2,f1,f2,x;
	do
	{
		cout<<"input x1,x2： ";
		cin>>x1>>x2;
		f1=f(x1);
		f2=f(x2);
	}
	while(f1*f2>=0);
	x=root(x1,x2);
	cout<<"A root of equation is： "<<x<<endl;
	return 0;
}
double f(double x)
{
	double y;
	y=x*x*x-5*x*x+16*x-80;
	return y;
}
double xpoint(double x1,double x2)
{
	double y;
	y=(x1*f(x2)-x2*f(x1))/(f(x2)-f(x1));
	return y;
}
double root(double x1,double x2)
{
	double x,y,y1;
	y1=f(x1);
	do
	{
		x=xpoint(x1,x2);
		y=f(x);
		if(y*y1>0)
		{
			y1=y;
			x1=x;
		}
		else x2=x;
	}
	while(fabs(y)>=0.00001);
	return x;
}
例4-6
/利用递归求解年龄问题；
#include "stdafx.h"
#include"iostream"

using namespace std;
int age(int);
int main()
{
	cout<<age(5)<<endl;
	return 0;
}
int age(int n)
{
	int c;
	if(n==1)
	{
		c=10;
	}
	else c=age(n-1)+2;
	return c;
}
例4-7
//编程求解1~10中各个数的平方；
#include "stdafx.h"
#include"iostream"

using namespace std;
inline int power_int(int x)
{
	return x*x;
}
void main()
{
	for(int i=1;i<=10;i++)
	{
		int p=power_int(i);
		cout<<i<<"*"<<i<<"="<<p<<endl;
	}
}

例4-8
//利用函数模板编写一个使用冒泡排序法进行排序的函数模板，并对int和char数组进行排序；
#include "stdafx.h"
#include"iostream"
using namespace std;


template<class T>
void B(T *list,int length)
{
	T  temp;
	for(int i=length-1;i>=1;i--)
	  for(int j=0;j<=i;j++)
	  {
		  if(list[j]<list[j+1])
		  {
			  temp=list[j];
			  list[j]=list[j+1];
			  list[j+1]=temp;
		  }
	  }
}
int main()
{
	int nums[]={1,2,3,9,5};
	B(nums,5);
	for(int i=0;i<5;i++)
	{
		cout<<nums[i]<<" ";
	}
	cout<<endl;
	char chars[]={'a','b','g','e','u','q'};
	B(chars ,6);
	for(int i=0;i<6;i++)
	{
		cout<<chars[i]<<" ";
	}
	return 0;
例5-1
//类的定义的示例；


class Tclock
{
public:
		void settime(int newH ,int newM ,int news);
	    void showtime();
private :
	int hour,minute,second;
};
void Tclock::settime(int H,int M,int S)
{
	hour=H;minute=M;second=S;
}
void Tclock::showtime ()
{
	cout<<hour<<":"<<minute <<":"<<second;
}



例5-2
//类的定义的示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class Tclock
{
public:
		void settime(int newH ,int newM ,int news);
	    void showtime();
private :
	int hour,minute,second;
	//void showtime();
};
void Tclock::settime(int H,int M,int S)
{
	hour=H;minute=M;second=S;
}
void Tclock::showtime ()
{
	cout<<hour<<":"<<minute <<":"<<second;
}
void main()
{
	Tclock c1;
	c1.settime (20,12,15);
	c1.showtime ();
}


例5-3
//对象的使用的示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class Tclock
{
public:
		void settime(int newH ,int newM ,int news);
	    void show();
private :
	int hour,minute,second;
	
};
class Tdate
{
public:
	int year,month,day;
	void setdate(int Y,int M,int D)
	{
		year=Y;month=M;day=D;
	}
	void show()
	{
		cout <<year<<"-"<<month<<"-"<<day<<endl;
	}
};
void Tclock::settime(int H,int M,int S)
{
	hour=H;minute=M;second=S;
}
void Tclock::show()
{
	cout<<hour<<":"<<minute <<":"<<second;
}
void main()
{
	Tclock c1;
	Tdate d1,*d2;
	d2=&d1;
	d2->setdate(2014,9,10);
	(*d2).show();
	c1.settime (20,12,15);
	c1.show();
}






例 5-4
//对象赋值示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

/*class Tclock
{
public:
		void settime(int newH ,int newM ,int news);
	    void showtime();
private :
	int hour,minute,second;
	
};*/
class Tdate
{
public:
	int year,month,day;
	void setdate(int Y,int M,int D)
	{
		year=Y;month=M;day=D;
	}
	void show()
	{
		cout <<year<<"-"<<month<<"-"<<day<<endl;
	}
};
/*void Tclock::settime(int H,int M,int S)
{
	hour=H;minute=M;second=S;
}
void Tclock::showtime ()
{
	cout<
void main()
{
	Tdate d1,d2;
	d1.setdate (2014,9,10);
	d1.show();
	d2.setdate (2014,10,10);
	d2.show();
	d1=d2;
	d1.show();
	d2.show();
}

例5-5
//内联函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class Tcircle
{
public:
	double area(double radius)
	{
		return 3.1415*radius*radius;
	}
};
void main()
{
	Tcircle c1;
	double r,s;
	cout<<"please input r:"<<endl;
	cin>>r;
	s=c1.area (r);
	cout<<"area="<<s<<endl;
}
例5-6
//内联函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class Tcircle
{
public:
	double area(double radius);
	
};
inline double Tcircle::area(double radius)
	{
		return 3.1415*radius*radius;
	}
void main()
{
	Tcircle c1;
	double r,s;
	cout<<"please input r:"<<endl;
	cin>>r;
	s=c1.area (r);
	cout<<"area="<<s<<endl;
}
例5-7
//构造函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class A
{
	float x,y;
public:
	A(float a,float b)
	{
		x=a;
		y=b;
	}
	void set(float a,float b)
	{
		x=a;
		y=b;
	}
	void print(void)
	{cout<<"x="<<x<<'\t'<<"y="<<y<<endl;
	}
};
void main()
{
	A a1(2,3);
	A a2(4,5);
	a2.set(7,8);
	a1.print();
	a2.print();
}

例5-8
//构造函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class record
{
private:
	char bookname[30];
	int number;
public:
	record();
	record(char *a,int b);
	void show();
};
record::record ()
{
	strcpy_s(bookname,"\0");
	number=0;
}
record::record(char *a,int b)
{   strcpy_s(bookname,a);
     number=b;
}
void record::show ()
{
	cout<<"bookname is:"<<bookname<<endl;
	cout<<"booknumber is :"<<number<<endl;
}
int main()
{
	record mybook("visual c++ 6.0",10020);
	mybook.show();
	record yourbook;
	yourbook.show();
}
例5-9
//构造函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class record
{
private:
	char bookname[30];
	int number;
public:

	record(char *a,int b);
	void show();
};

record::record(char *a="vc++",int b=10020)
{   strcpy_s(bookname,a);
     number=b;
}
void record::show ()
{
	cout<<"bookname is:"<<bookname<<endl;
	cout<<"booknumber is :"<<number<<endl;
}
int main()
{
	record mybook;
	mybook.show();
	
}
例5-10
//析构函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class teacher
{
	char *name;
	int age;
public:
	teacher(char *i,int a)
	{
		name=new char[strlen(i)+1];
		strcpy(name ,i);
		age=a;
		cout<<"\n执行构造函数teacher"<<endl;
	}
	~teacher()
	{
		delete[] name;
		cout<<"执行析构函数"<<endl<<endl;
	}
	void show()
	{
		cout<<"姓名："<<name<<"  "<<"年龄："<<age<<endl;
	}
};
int main()
{
	teacher obj("张立三",25);
	obj.show();
}
例5-11
//析构函数示例；
#include "stdafx.h"
#include"iostream"
using namespace std;

class A
{
	float x,y;
public:
	A(float a,float b)
	{  x=a;y=b;
	cout<<"初始化自动局部对象\n";
	}
	A()
	{  x=0;y=0;
	cout<<"初始化静态局部对象\n";
	}
	A(float a)
	{ x=a;y=0;
	cout<<"初始化全局对象\n";
	}
	~A()
	{cout<<"调用析构函数"<<endl;
	}
};//
A a0(100.0);
void f(void)
{
	cout<<"进入f（）函数"<<endl;
	A ab(10.0,20.0);
	static A a3;
}
void main()
{
	cout<<"进入main函数"<<endl;
	f();f();
}
例5-12
//通过类名访问静态数据成员；
#include "stdafx.h"
#include"iostream"
using namespace std;

class counter
{
public:
	static int num;
};
int counter::num=0;
void main()
{
	counter::num=20;
	cout<<counter::num<<endl;
}
例5-13
//通过对象名访问静态数据成员；
#include "stdafx.h"
#include"iostream"
using namespace std;

class counter
{
public:
	static int num;
	counter(){cout<<++num<<" ";}
   ~counter(){cout<<--num<<" ";}//main函数结束后系统自动调用析构函数
};
int counter::num=0;
void main()
{
	counter a,b,c;//调用三次构造函数
	cout<<endl;
	cout<<a.num<<endl;
	cout<<counter::num<<endl;
}

例5-14
//this指针的应用；
#include "stdafx.h"
#include"iostream"
using namespace std;

class point
{
private:
	int x,y;
public:
	point(int a,int b)
	{
		x=a;
		y=b;
	}
	void movepoint(int a,int b)
	{
		x+=a;
		y+=b;
	}
	void print()
	{
		cout<<"x="<<x<<"y="<<y<<endl;
	}
};

int main()
{
	point point1(10,10);
	point1.movepoint(2,2);
	point1.print();
	return 0;
}
例5-15
//友元函数的应用
#include "stdafx.h"
#include"iostream"
#include"math.h"
using namespace std;

class point
{
private:
	int x,y;
public:
	point(int xx=0,int yy=0)
	{
		x=xx;
		y=yy;
	}
	friend double distance(point &a,point &b);//distance函数可以访问point中的成员，包括私有成员；
};
double distance(point &a,point &b)
{
	double dx=a.x-b.x;
	double dy=a.y-b.y;
	return sqrt(dx*dx+dy*dy);
}

int main()
{
	point p1(3.0,5.0),p2(4.0,6.0);
	double d=distance(p1,p2);
	cout<<"the distance is"<<d<<endl;
	return 0;
}


例5-16
//友元类的应用
#include "stdafx.h"
#include"iostream"
using namespace std;

class X         /
{
public:
	friend class Y;
	void set(int i)
	{
		x=i;
	}
	void display()
	{
		cout<<"x="<<x<<"y="<<y<<endl;
	}
private:
	int x;
	static int y;
};
class Y    ///
{
public:
	Y(int i,int j);
	void display();
private:
	X a;
};

int X::y=10;     ///

Y::Y(int i,int j)
{
	a.x=i;
	X::y=j;
}
void Y::display()   ///
{
	cout<<"x="<<a.x<<"y="<<a.y<<endl;
}
void main()
{
	X b;
	b.set(5);
	b.display();
	Y c(6,9);
	c.display();
	b.display();
}


例6-1
//成员函数重载
#include "stdafx.h"
#include"iostream"
using namespace std;

class sample
{
private:
	int i;
	double d;
public:
	void setdata(int n){i=n;d=0;}
	void setdata(int n,double x){i=n,d=x;}
	void disp()
	{ cout<<"i="<<i<<",d="<<d<<endl;
	}
};
void main()
{
	sample s;
	s.setdata(15);
	s.disp();
	s.setdata(20,23.8);
	s.disp();
}


例6-2
//双目运算符重载示例
#include "stdafx.h"
#include"iostream"
using namespace std;

class complex
{
public:
	complex(){real=imag=0;}
	complex(double r,double i){real=r;imag=i;}
	complex operator +(const complex &c);
	friend void print(const complex &c);
private:
	double real,imag;
};
inline complex complex::operator+(const complex &c)
{
	return complex(real +c.real,imag+c.imag);
}
void print(const complex &c)
{
	cout<<c.real<<"+"<<c.imag<<"i";
}
void main()
{
	complex c1(2.0,3.0),c2(4.0,-2.0),c3;
	c3=c1+c2;
	cout<<"c1+c2=";
	print(c3);

}

例6-3
//单目运算符重载示例
#include "stdafx.h"
#include"iostream"
using namespace std;

class time
{
public:
	time(){minute=0;sec=0;}
	time(int m,int s):minute(m),sec(s){}
	time operator++();
	void display(){cout<<minute<<":"<<sec<<endl;}
private:
	int minute;
	int sec;
};
time time::operator++()
{
	if(++sec>=60)
	{
		sec-=60;
		++minute;
	}
	return *this;
}
int main()
{
	time time1(34,0);
	for(int i=0;i<60;i++)
	{
		++time1;
		time1.display();
	}
	return 0;
}




例6-4
//修改例6-3位运算符重载位类的友元函数
#include "stdafx.h"
#include"iostream"
using namespace std;

class time
{
public:
	time(){minute=0;sec=0;}
	time(int m,int s):minute(m),sec(s){}
	friend time operator++(time &a);
	void display(){cout<<minute<<":"<<sec<<endl;}
private:
	int minute;
	int sec;
};
time operator++(time &a)
{
	if(++a.sec>=60)
	{
		a.sec-=60;
		++a.minute;
	}
	return a;
}
int main()
{
	time time1(34,0);
	for(int i=0;i<60;i++)
	{
		++time1;
		time1.display();
	}
	return 0;
}





例6-5
//派生类示例1
#include "stdafx.h"
#include"iostream"
using namespace std;

class A
{
private:
	int privA;
protected:
	int protA;
public:
	int pubA;
};
class C:protected A
{
public:
void fn()
{
	int a;
	a=privA;
	a=protA;
	a=pubA;
}
};

void main()
{
	C obj2;
	obj2.privA=1;
	obj2.protA=1;
	obj2.pubA=1;
}


例6-6
/派生类构造函数和析构函数的示例
#include "stdafx.h"
#include"iostream"
using namespace std;

class parent_class
{
	int private1,private2;
public:
	parent_class(int p1,int p2):private1(p1),private2(p2)
	{}
	int inc1()
	{	return ++private1;
    }
	void display()
	{
		cout<<"private1="<<private1<<",private2="<<private2<<endl;
	}
};
class derived_class:private parent_class
{
	int private3;
	parent_class obj4;
public:
	derived_class(int p1,int p2,int p3,int p4,int p5):parent_class(p1,p2),obj4(p3,p4),private3(p5)
	{}
	int inc1()
	{
		return parent_class::inc1();
	}
	void display()
	{
		parent_class::display();
		obj4.display();
		cout<<"private3="<<private3<<endl;
	}
};
void main()
{
	derived_class d1(18,18,1,2,-5);
	d1.inc1();
	d1.display();
}

例6-7
//多重继承示例
#include "stdafx.h"
#include"iostream"
using namespace std;

class A
{
	int a;
public:
	A(int i)
	{
		a=i;
		cout<<"A constructor"<<endl;
	}
	void view()
	{
		cout<<"a="<<a<<endl;
	}
};
class B
{
	int b;
public:
	B(int j)
	{
		b=j;
		cout<<"B constructor"<<endl;
	}
	void view()
	{
		cout<<"b="<<b<<endl;
	}
};
class C:public A,public B
{
	int c;
public:
	C(int k):A(++k),B(--k)
	{
		c=k;
		cout<<"C constructor"<<endl;
	}
	void view()
	{
		A::view();
		B::view();
		cout<<"c="<<c<<endl;
	}
};
void main()
{
	C c1(10);
	c1.view();
}





例6-8
//赋值相容示例
#include "stdafx.h"
#include"iostream"
using namespace std;
#include"string"

class ABCBase
{
private:
	string ABC;
public:
	ABCBase(string abc)
	{
		ABC=abc;
	}
	void showABC();
};

void ABCBase::showABC()
{
	cout<<"字母ABC=>"<<ABC<<endl;
}
class X:public ABCBase
{
public:
	X(string x):ABCBase(x){}
};
void function(ABCBase &base)
{
	base.showABC();
}
int main()
{
	ABCBase base("A");
	base.showABC();
	X x("B");
	base=x;
	base.showABC();
	ABCBase &base1=x;
	base1.showABC();
	ABCBase *base2=&x;
	base2->showABC();
	function(x);
	return 0;
}
例6-9
//非虚函数方式实现日期显示示例
#include "stdafx.h"
#include"iostream"
using namespace std;


class base
{
protected:
	int year;
public:
	base(int y)
	{
		year=y;
	}
	void display()
	{
		cout<<"year="<<year<<endl;
	}
};
class second:public base
{
protected:
	int month;
public:
	second(int y,int m):base(y)
	{
		month=m;
	}
	void display()
	{
		cout<<"year-month"<<year<<"-"<<month<<endl;
	}
};
class third:public second
{
	int day;
public:
	third(int y,int m,int d):second(y,m)
	{
		day=d;
	}
	void display()
	{
		cout<<"year-month-day"<<year<<"-"<<month<<"-"<<day<<endl;
	}
};
int main()
{
	base b(2015);
	second s(2015,1);
	third t(2015,1,20);
	base *p;
	p=&b;
	p->display();
	p=&s;
	p->display();
	((second*)p)->display();
	p=&t;
	p->display();
	((third*)p)->display();
	return 0;
}


例6-10
//虚函数应用
#include "stdafx.h"
#include"iostream"
using namespace std;


class base
{
protected:
	int year;
public:
	base(int y)
	{
		year=y;
	}
virtual void display()
	{
		cout<<"year="<<year<<endl;
	}
};
class second:public base
{
protected:
	int month;
public:
	second(int y,int m):base(y)
	{
		month=m;
	}
	void display()
	{
		cout<<"year-month"<<year<<"-"<<month<<endl;
	}
};
class third:public second
{
	int day;
public:
	third(int y,int m,int d):second(y,m)
	{
		day=d;
	}
	void display()
	{
		cout<<"year-month-day"<<year<<"-"<<month<<"-"<<day<<endl;
	}
};
int main()
{
	base b(2015);
	second s(2015,1);
	third t(2015,1,20);
	base *p;
	p=&b;
	p->display();
	p=&s;
	p->display();
	p->display();
	p=&t;
	p->display();
	p->display();
	return 0;
}




例6-11
//虚函数应用
#include "stdafx.h"
#include"iostream"
using namespace std;


class base
{
public:
	~base()
	{
		cout<<"~base()is called"<<endl;
	}
};
class derived:public base
{
public:
	~derived()
	{
		cout<<"~dervied() is called"<<endl;
	}	
};
int main()
{
	derived *p1=new derived;
	cout<<"delete p1:"<<endl;
	delete p1;
	base *p2=new derived;
	cout<<endl<<"delete p2:"<<endl;
	delete p2;
	base *p3=new derived;
	cout<<endl<<"delete p3:"<<endl;
	delete(derived*) p3;
	cout<<endl;
	return 0;
}
例6-12
//虚函数应用
#include "stdafx.h"
#include"iostream"
using namespace std;


class base
{
public:
	virtual ~base()
	{
		cout<<"~base()is called"<<endl;
	}
};
class derived:public base
{
public:
	~derived()
	{
		cout<<"~dervied() is called"<<endl;
	}	
};
int main()
{
	base *p3=new derived;
	cout<<endl<<"delete p3:"<<endl;
	delete  p3;
	cout<<endl;
	return 0;
}
例6-13
//简单异常处理示例
#include "stdafx.h"
#include"iostream"
using namespace std;

int main()
{
	int m,n;
	cout<<"please input two inteders:";
	cin>>m>>n;
	try
	{
		if(n==0)
			throw 0;
		cout<<(m/n)<<endl;
	}
	catch(int)
	{
		cout<<"divided by 0!"<<endl;
		return -1;
	}
}
例6-13
//简单异常处理示例
#include "stdafx.h"
#include"iostream"
using namespace std;

int main()
{
	int m,n;
	cout<<"please input two inteders:";
	cin>>m>>n;
	try
	{
		if(n==0)
			throw 0;
		cout<<(m/n)<<endl;
	}
	catch(int)
	{
		cout<<"divided by 0!"<<endl;
		return -1;
	}
	return 0;
}
例6-14
/成员函数抛出异常示例
#include "stdafx.h"
#include"iostream"
using namespace std;

class complex
{
public:
	complex(){real=0;imag=0;}
	complex(double r,double i){real=r;imag=i;}
	complex divide(const complex x);
	void display();
private:
	double real;
	double imag;
};
void complex::display()
{
	cout<<"("<<real<<"+"<<imag<<"i)"<<endl;}
		complex complex::divide(const complex x)
	{
		float c=x.real*x.real+x.imag*x.imag;
		if(c==0)
			throw 0;
		return 
			complex((real*x.real+imag*x.imag)/c,(x.real*imag-real*x.imag)/c);
	}
	int main()
	{
		complex x(1,1), y(0,0),z;
		try
		{
			z=x.divide(y);
			z.display();
		}
		catch(int)
		{
			cout<<"error:divided by zeros!"<<endl;
		}
		return 1;
	}


例6-15
//标准异常类示例
#include "stdafx.h"
#include"iostream"
#include"string"
using namespace std;
void main()
{
	char *buf;
	try
	{
		buf=new char[100];
		if(buf==0)throw bad_alloc();
	}
	catch(bad_alloc)
	{
		cout<<"内存分配失败"<<endl;
	}
	getchar();
}

例6-15
// p2_1.cpp : 定义控制台应用程序的入口点。
//
//自定义异常类示例
#include "stdafx.h"
#include"iostream"
#include"string"
using namespace std;
class zerodivide
{
public:
	zerodivide(string desc)
	{
		this->desc=desc;
	}
	string getmessage()
	{return desc;}

private:string desc;
};
int divide(int x,int y)
{
	if(y==0) throw zerodivide("除数为");
	return x/y;
}
int main()
{
	int x,y;
	cout<<"输入两个数：";
	while(cin>>x>>y)
	{
		try
		{
			cout<<divide(x,y)<<endl;
		}
		catch(zerodivide e){
			cout<<e.getmessage()<<endl;
		}
		cout<<"继续输入数值<退出>";
	}
	return 0;
}