第6次cplus实验

一。实验结论：

1.（1）类的声明：

#include<iostream>
using namespace std;
class A
{
    public:
        A(int m,int n);
        void plus();
        void minus();
    protected:
        int a;
        int b;
};
class B:public A
{
    public:
        B(int m,int n):A(m,n){}
        void multi();
};
class C:public A
{
    public:
        C(int m,int n):A(m,n){}
        void divi();
};

（2）类的实现：

#include"math.h"
#include<iostream>
using namespace std;
A::A(int m,int n)
{
    a=m;
    b=n;
}
void A::plus()
{
    int p;
    p=a+b;
    cout<<"The result is:"<<p<<endl;
}
void A::minus()
{
    int p;
    p=a-b;
    cout<<"The result is:"<<p<<endl;
}
void B::multi()
{
    int p;
    p=a*b;
    cout<<"The result is:"<<p<<endl;
}
void C::divi()
{
    double p;
    if(b==0)
        cout<<"Error!"<<endl;
    else
    {
        p=(double)a/(double)b;
        cout<<"The result is:"<<p<<endl;
    }
}

（3）主函数：

#include<iostream>
#include"math.h"
using namespace std;
int main() 
{
    int m,n;
    char p;
    while(1)
    {
        cout<<"Please input an equation, input 000 to exit:";
        cin>>m>>p>>n;
        if(m==0&&p=='0'&&n==0)
            break;
        else
        {
            if(p=='+')
            {
                A a(m,n);
                B b(m,n);
                C c(m,n);
                a.plus();
                b.plus();
                c.plus();
            }
            else if(p=='-')
            {
                A a(m,n);
                a.minus();
            }
            else if(p=='*')
            {
                B a(m,n);
                a.multi();
            }
            else if(p=='/')
            {
                C a(m,n);
                a.divi();
            }
            else
            {
                cout<<"Error!"<<endl;
                continue;
            }
        }
    }
    return 0;
}

（4）运行结果：

2.（1）代码：

#include<iostream>
using namespace std;
class vehicle
{
    public:
        vehicle(int m,int w):maxspeed(m),weight(w)
        {
            cout<<"Vehicle is constructing..."<<endl;
            cout<<"The max speed is:"<<maxspeed<<endl;
            cout<<"The weight is:"<<weight<<endl;
        }
        void run()
        {
            cout<<"Running..."<<endl;
        }
        void stop()
        {
            cout<<"Stopped."<<endl;
        }
        ~vehicle()
        {
            
            cout<<"Vehicle has been destructed."<<endl;
        }
    protected:
        int maxspeed;
        int weight;
};
class bicycle:virtual public vehicle
{
    public:
        bicycle(int m,int w,int h):vehicle(m,w),height(h)
        {
            cout<<"Bicycle is constructing..."<<endl;
            cout<<"The height is:"<<height<<endl;
        }
        ~bicycle()
        {
            cout<<"Bicycle has been destructed."<<endl;
        }
    protected:
        int height;
};
class motorcar:virtual public vehicle
{
    public:
        motorcar(int m,int w,int s):vehicle(m,w),seatnum(s)
        {
            cout<<"Motorcar is constructing..."<<endl;
            cout<<"The seatnum is:"<<seatnum<<endl;
        }
        ~motorcar()
        {
            cout<<"Motorcar has been destructed."<<endl;
        }
    protected:
        int seatnum;
};
class motorbike:public bicycle,public motorcar
{
    public:
        motorbike(int m,int w,int h,int s):vehicle(m,w),bicycle(m,w,h),motorcar(m,w,s){}
        ~motorbike()
        {
            cout<<"Motorbike has been destructed."<<endl;
        }
};
int main()
{
    int a,b,c,d;
    cout<<"Please input the maxspeed,weight,height,seatnum of the motorbike:";
    cin>>a>>b>>c>>d;
    motorbike M(a,b,c,d);
    M.run();
    M.stop();
    return 0;
}

（2）运行结果：

3.（1）类的声明：

//#include"Fraction.h"
#include<iostream>
using namespace std;
class iFraction:public Fraction
{
    public:
        iFraction(int p=0,int q=1,int n=0):Fraction(p,q),number(n){}
        void show();
    private:
        int itop;
        int ibottom;
        int number;
};

（2）类的实现：

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#include"iFraction.h"
#include<iostream>
using namespace std;
void iFraction::show()
{
    if(bottom==0)
        cout<<"Error!"<<endl;
    else if(top==0)
        cout<<number<<endl;
    else if(top%bottom==0)
    {
        number=number+top/bottom;
        cout<<number<<endl;
    }
    else if(top>bottom)
    {
        number=number+top/bottom;
        top=top%bottom;
        cout<<"   "<<top<<endl;
        cout<<number<<"------"<<endl;
        cout<<"   "<<bottom<<endl;
    }
    else if(number==0)
    {
        cout<<"  "<<top<<endl;
        cout<<"------"<<endl;
        cout<<"  "<<bottom<<endl;
    }
    else
    {
        cout<<"   "<<top<<endl;
        cout<<number<<"------"<<endl;
        cout<<"   "<<bottom<<endl;
    }
}

（3）主函数

#include"Fraction.h"
#include"iFraction.h"
#include<iostream>
#include<stdlib.h>
using namespace std;
int main()
{
    int x,y,z;
    Fraction a;a.output();
    Fraction b(3,6);b.output();
    Fraction c(5);c.output();
    b.compare(c);
    cout<<"Please input the top and the bottom:";
    cin>>x>>y;
    Fraction d(x,y);d.opera(x,y);d.output();
    cout<<"Please input a number:";
    cin>>z;
    iFraction e(x,y,z);e.opera(x,y);e.show();
    return 0;
}

（4）运行结果：

二。实验分析与讨论

　　实验第三题类的声明中，有时取消第一行的注释后编译成功，而有时注释第一行后编译成功，至于什么原因我也没有搞明白，麻烦大佬们在评论时帮我解答一下。。。。

　　通过这次实验，我初步掌握了最近的新知识继承与多态的大致概念以及使用方法，也发现了自己在所学知识的掌握方面的诸多不足，在以后的时间里，我还需要多加练习。