一道派生类的构造函数问题

hui135 2009-05-23 10:46:56
//定义一个大学生类Graduate，私有数据成员：姓名，学号，校名，
//并为它定义带参数的构造函数、拷贝构造函数、析构函数和
//输出数据成员值的print( )公有成员函数，另定义研究生类Postgraduate，
//它以公有继承方式派生于类Graduate，新增加"研究方向、导师名"两个私有数据成员，
//并定义带参数的构造函数，拷贝构造函数、析构函数和输出研究生数据的print( )公有成员函数，
//另外，要求学号自动增加，且Graduate和Postgraduate的学号起始值不同。
//在主函数中定义派生类对象进行测试。(字符串用char*表示)

#include<iostream.h>
#include<string.h>

class Graduate
{
public:
Graduate(char *gname,char *gnumber,char *guniversity);
void print();
void setname(char *pname)
{
strcpy(name,pname);
}
char* getname()
{
return name;
}
Graduate(const Graduate &p);
~Graduate();
private:
char *name;
char *number;
char *university;
};

Graduate::Graduate(char *gname,char *gnumber,char *guniversity)
{
name=new char[10];
strcpy(name,gname);
number=new char[10];
strcpy(number,gnumber);
university=new char[20];
strcpy(university,guniversity);
}

void Graduate::print()
{
cout<<" your name:"<<name<<endl;
cout<<" your number:"<<number<<endl;
cout<<" your university:"<<university<<endl;
}

Graduate::Graduate(const Graduate &p)
{
name=new char[strlen(p.name)+1];
strcpy(name,p.name);
number=new char[strlen(p.number)+1];
strcpy(number,p.name);
university=new char[strlen(p.university)+1];
strcpy(university,p.university);
}

Graduate::~Graduate()
{
delete[] name;
delete[] number;
delete[] university;
}

class Postgraduate:public Graduate
{
public:
Postgraduate(char *gname,char *gnumber,char *pdirection,char *ptutor):Graduate(gname,gnumber)
{
direction=new char[20];
strcpy(direction,pdirection);
tutor=new char[10];
strcpy(tutor,ptutor);
}
void print();
// Postgraduate(const Postgraduate &k0);
~Postgraduate();
private:
char *direction;
char *tutor;
};

void Postgraduate::print()
{

cout<<" your direction:"<<direction<<endl;
cout<<" your tutor:"<<tutor<<endl;
}

/*
Postgraduate::Postgraduate(const Postgraduate &k0)
{
setname(k0.getname);
number=new char[strlen(pnumber)+1];
strcpy(number,pnumber);

direction=new char[strlen(k0.direction)+1];
strcpy(direction,k0.direction);
tutor=new char[strlen(k0.tutor)+1];
strcpy(tutor,k0.tutor);

}
*/

Postgraduate::~Postgraduate()
{
delete[] direction;
delete[] tutor;
}

void main()
{
char name[10];
char number[10];
char university[20];
char direction[20];
char tutor[10];
cout<<"please input your name:"<<endl;
cin>>name;
cout<<"please input your number:"<<endl;
cin>>number;
cout<<"please input your university:"<<endl;
cin>>university;
Graduate b(name,number,university);
b.print();

cout<<"please input your name:"<<endl;
cin>>name;
cout<<"please input your number:"<<endl;
cin>>number;
cout<<"please input your direction:"<<endl;
cin>>direction;
cout<<"please input your tutor:"<<endl;
cin>>tutor;
Postgraduate a(name,number,direction,tutor);
a.print();
}
在vc6.0中编译出错：
Cpp3-1.cpp(71) : error C2661: 'Graduate::Graduate' : no overloaded function takes 2 parameters
哪位大侠知道怎么回事，怎么解决，幸苦你了。
...全文
190 23 打赏 收藏 转发到动态 举报
写回复
用AI写文章
23 条回复
切换为时间正序
请发表友善的回复…
发表回复
chenling4063598 2009-05-25
  • 打赏
  • 举报
 回复
上面这个可以了，我以前发的就是那个默认的Graduate();没有加{}；
现在可以了，你试试~
chenling4063598 2009-05-25
  • 打赏
  • 举报
 回复
#include <iostream.h>
#include <string.h>

class Graduate
{
static int number;
public:
//Graduate(char *gname,int gnumber,char *guniversity);
Graduate(char *gname,char *guniversity);
Graduate(){};

void print();

void setname(char *pname)
{
strcpy(name,pname);
}
/*void setnumber(char *pnumber)
{
strcpy(name,pnumber);
}*///add setnumber.as the number is private for Graduate.

char* getname()
{
return name;
}
int* getnumber()
{
return &gnumber;
}

Graduate(const Graduate &p); //space

~Graduate();

protected:
char *name;
int gnumber;
char *university;
};

Graduate::Graduate(char *gname,char *guniversity)
{
name=new char[strlen(gname)+1]; //用strlen(gname)+1代替固定的值
strcpy(name,gname);
/*number=new char[strlen(gnumber)+1];
strcpy(number,gnumber); */
gnumber=number+1;
university=new char[strlen(guniversity)+1];
strcpy(university,guniversity);
}

void Graduate::print()
{
cout <<" your name:" <<name <<endl;
cout <<" your number:" <<gnumber<<endl;
cout <<" your university:" <<university<<endl;
}

Graduate::Graduate(const Graduate&p)
{
name=new char[strlen(p.name)+1];
strcpy(name,p.name);
/*number=new char[strlen(p.number)+1];
strcpy(number,p.number); */
gnumber=number+1;
university=new char[strlen(p.university)+1];
strcpy(university,p.university);
}

Graduate::~Graduate()
{
delete[] name;
//delete[] number;
delete[] university;
}

class Postgraduate:public Graduate
{
static int pnumber;
public:
Postgraduate(char *gname,char *guniversity,char *pdirection,char *ptutor):Graduate(gname,guniversity)
{

direction=new char[strlen(pdirection)+1];
strcpy(direction,pdirection);

*getnumber()=pnumber+1;//not very clearly
tutor=new char[strlen(ptutor)+1];
strcpy(tutor,ptutor);
}
void print();
Postgraduate(const Postgraduate &k);
~Postgraduate();
private:
//int ponumber;
char *direction;
char *tutor;
};

void Postgraduate::print()
{
/*cout <<" your name:" <<name <<endl;
cout <<" your number:" <<gnumber<<endl;
cout <<" your university:" <<university<<endl; */
//cout <<" your number:" <<getnumber<<endl;
cout <<" your direction:" <<direction <<endl;
cout <<" your tutor:" <<tutor <<endl;
}


Postgraduate::Postgraduate(const Postgraduate &k) //这一块属于继承类的复制构造函数？没用过，不知道为什么要调用无参构造函数Gradute
{
//name=new char[strlen(k.name)+1];

setname(k.name);
gnumber=pnumber+1;
university=new char[strlen(k.university)+1];
strcpy(university,k.university);

//number=new char[strlen(pnumber)+1];
//strcpy(number,pnumber);
//setnumber(k,getnumber);

direction=new char[strlen(k.direction)+1];
strcpy(direction,k.direction);
tutor=new char[strlen(k.tutor)+1];
strcpy(tutor,k.tutor);

}


Postgraduate::~Postgraduate()
{
delete[] direction;
delete[] tutor;
}

int Graduate::number=0;
int Postgraduate::pnumber =0;

void main()
{
char name[10];
//char number[10];
char university[20];
char direction[20];
char tutor[10];
cout <<"please input your name:" <<endl;
cin>>name;
//cout <<"please input your number:" <<endl;
//cin>>number;
cout <<"please input your university:" <<endl;
cin>>university;
Graduate b(name,university);
b.print();

cout <<"please input your name:" <<endl;
cin>>name;
//cout <<"please input your number:" <<endl;
//cin>>number;
cout <<"please input your direction:" <<endl;
cin>>direction;
cout <<"please input your university:" <<endl;
cin>>university;
cout <<"please input your tutor:" <<endl;
cin>>tutor;
Postgraduate a(name,university,direction,tutor);
a.print();
}


ltc_mouse 2009-05-24
  • 打赏
  • 举报
 回复
对于派生类的构造函数，首先应该完成的是基类数据的初始化（调用基类某种形式的构造函数），然后是新增加的派生类数据初始化~
拷贝构造函数也是如此。先基类的拷贝构造，再新增的成员数据~ 这样达到各个层次尽量只对自己添加的数据“负责”~


Postgraduate::Postgraduate(const Postgraduate &k0):Graduate(k0)

{

   direction=new char[strlen(k0.direction)+1]; 

   strcpy(direction,k0.direction); 

   tutor=new char[strlen(k0.tutor)+1]; 

   strcpy(tutor,k0.tutor); 

}
pengzhixi 2009-05-24
  • 打赏
  • 举报
 回复
Postgraduate(char *gname,char *gnumber,char *pdirection,char *ptutor):Graduate(gname,gnumber) //问题在这,你调用基类构造函数时,参数传少了
{
direction=new char[20];
strcpy(direction,pdirection);
tutor=new char[10];
strcpy(tutor,ptutor);
}
chenling4063598 2009-05-24
  • 打赏
  • 举报
 回复
你写的这个程序的学号没有按照要求编。
学号对于大学生和研究生的基数是不一样的。
chenling4063598 2009-05-24
  • 打赏
  • 举报
 回复
#include <iostream.h>
#include <string.h>

class Graduate
{
static int number;
public:
//Graduate(char *gname,int gnumber,char *guniversity);
Graduate(char *gname,char *guniversity);
Graduate();
void print();

void setname(char *pname)
{
strcpy(name,pname);
}
/*void setnumber(char *pnumber)
{
strcpy(name,pnumber);
}*///add setnumber.as the number is private for Graduate.

char* getname()
{
return name;
}
int* getnumber()
{
return &gnumber;
}

Graduate(const Graduate &p); //space

~Graduate();

protected:
char *name;
int gnumber;
char *university;
};

Graduate::Graduate(char *gname,char *guniversity)
{
name=new char[strlen(gname)+1]; //用strlen(gname)+1代替固定的值
strcpy(name,gname);
/*number=new char[strlen(gnumber)+1];
strcpy(number,gnumber); */
gnumber=number+1;
university=new char[strlen(guniversity)+1];
strcpy(university,guniversity);
}

void Graduate::print()
{
cout <<" your name:" <<name <<endl;
cout <<" your number:" <<gnumber<<endl;
cout <<" your university:" <<university<<endl;
}

Graduate::Graduate(const Graduate&p)
{
name=new char[strlen(p.name)+1];
strcpy(name,p.name);
/*number=new char[strlen(p.number)+1];
strcpy(number,p.number); */
gnumber=number+1;
university=new char[strlen(p.university)+1];
strcpy(university,p.university);
}

Graduate::~Graduate()
{
delete[] name;
//delete[] number;
delete[] university;
}

class Postgraduate:public Graduate
{
static int pnumber;
public:
Postgraduate(char *gname,char *guniversity,char *pdirection,char *ptutor):Graduate(gname,guniversity)
{

direction=new char[strlen(pdirection)+1];
strcpy(direction,pdirection);

*getnumber()=pnumber+1;//not very clearly
tutor=new char[strlen(ptutor)+1];
strcpy(tutor,ptutor);
}
void print();
Postgraduate(const Postgraduate &k);
~Postgraduate();
private:
//int ponumber;
char *direction;
char *tutor;
};

void Postgraduate::print()
{
/*cout <<" your name:" <<name <<endl;
cout <<" your number:" <<gnumber<<endl;
cout <<" your university:" <<university<<endl; */
//cout <<" your number:" <<getnumber<<endl;
cout <<" your direction:" <<direction <<endl;
cout <<" your tutor:" <<tutor <<endl;
}


Postgraduate::Postgraduate(const Postgraduate &k)
{
//name=new char[strlen(k.name)+1];

setname(k.name);
gnumber=pnumber+1;
university=new char[strlen(k.university)+1];
strcpy(university,k.university);

//number=new char[strlen(pnumber)+1];
//strcpy(number,pnumber);
//setnumber(k,getnumber);

direction=new char[strlen(k.direction)+1];
strcpy(direction,k.direction);
tutor=new char[strlen(k.tutor)+1];
strcpy(tutor,k.tutor);

}


Postgraduate::~Postgraduate()
{
delete[] direction;
delete[] tutor;
}

int Graduate::number=0;
int Postgraduate::pnumber =0;

void main()
{
char name[10];
//char number[10];
char university[20];
char direction[20];
char tutor[10];
cout <<"please input your name:" <<endl;
cin>>name;
//cout <<"please input your number:" <<endl;
//cin>>number;
cout <<"please input your university:" <<endl;
cin>>university;
Graduate b(name,university);
b.print();

cout <<"please input your name:" <<endl;
cin>>name;
//cout <<"please input your number:" <<endl;
//cin>>number;
cout <<"please input your direction:" <<endl;
cin>>direction;
cout <<"please input your university:" <<endl;
cin>>university;
cout <<"please input your tutor:" <<endl;
cin>>tutor;
Postgraduate a(name,university,direction,tutor);
a.print();
}


Linking...
test01.obj : error LNK2001: unresolved external symbol "public: __thiscall Graduate::Graduate(void)" (??0Graduate@@QAE@XZ)
Debug/test1.exe : fatal error LNK1120: 1 unresolved externals
执行 link.exe 时出错.
变成这样了
test1.exe - 1 error(s), 0 warning(s)
变成这样了
hui135 2009-05-23
  • 打赏
  • 举报
 回复
下了，郁闷！明天在来！！！
arong1234 2009-05-23
  • 打赏
  • 举报
 回复
请继续
[Quote=引用 15 楼 hui135 的回复:]
但我就是要问，你看着吧，总会有人回答的！！！[/Quote]
hui135 2009-05-23
  • 打赏
  • 举报
 回复
14楼说得有理，不过要是我们都一点就通那还要提问干嘛，像G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(95) : error C2664: 'setname' : cannot convert parameter 1 from 'char *(void)' to 'char *'
There is no context in which this conversion is possible

我当然知道怎么回事，我们能提出问题来，都是自己下面想了很久，查过书，还是不太清楚才问嘛，想从其他高手那里得到写意见，论坛里难道新手就不能问些“弱智”问题吗，所以我说我你就是偏见，看不起我们新手。但我就是要问，你看着吧，总会有人回答的！！！
arong1234 2009-05-23
  • 打赏
  • 举报
 回复
别人只能给你方向性的指导，如果你不能触类旁通，根据人家的指导找到其他问题的答案，总是等着别人堆每个出的错误都指导一下，那什么时候是个完？
arong1234 2009-05-23
  • 打赏
  • 举报
 回复
首先你还是没懂啦，别人告诉你的是一类问题，而你只会你所举例子中涉及的函数，根本没有触类旁通


简单的说：如果你想调用一个函数（无论是不是构造函数），你必须满足人家参数列表的要求。参数列表要求你提供什么类型的参数，提供几个参数你都必须严格遵守
看看下面的错误：

G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(95) : error C2664: 'setname' : cannot convert parameter 1 from 'char *(void)' to 'char *'
There is no context in which this conversion is possible

从这个错误信息难道你还看不出他到底怎么了？人家要的是char*类型，你为什么传一个函数指针char*(void)给他？

[Quote=引用 12 楼 hui135 的回复:]
感谢lpf000等大侠，我知道怎么回事了，不过我对派生类的复制函数还有点问题：
#include <iostream.h>
#include <string.h>

class Graduate
{
public:
Graduate(char *gname,char *gnumber,char *guniversity);
void print();
void setname(char *pname)
{
strcpy(name,pname);
}
char* getname()
{
return name;
}
Graduate(const Graduate &p);
~Graduate();
private:
char *name;
c…
[/Quote]
hui135 2009-05-23
  • 打赏
  • 举报
 回复
感谢lpf000等大侠，我知道怎么回事了，不过我对派生类的复制函数还有点问题：
#include<iostream.h>
#include<string.h>

class Graduate
{
public:
Graduate(char *gname,char *gnumber,char *guniversity);
void print();
void setname(char *pname)
{
strcpy(name,pname);
}
char* getname()
{
return name;
}
Graduate(const Graduate &p);
~Graduate();
private:
char *name;
char *number;
char *university;
};

Graduate::Graduate(char *gname,char *gnumber,char *guniversity)
{
name=new char[10];
strcpy(name,gname);
number=new char[10];
strcpy(number,gnumber);
university=new char[20];
strcpy(university,guniversity);
}

void Graduate::print()
{
cout<<" your name:"<<name<<endl;
cout<<" your number:"<<number<<endl;
cout<<" your university:"<<university<<endl;
}

Graduate::Graduate(const Graduate &p)
{
name=new char[strlen(p.name)+1];
strcpy(name,p.name);
number=new char[strlen(p.number)+1];
strcpy(number,p.name);
university=new char[strlen(p.university)+1];
strcpy(university,p.university);
}

Graduate::~Graduate()
{
delete[] name;
delete[] number;
delete[] university;
}

class Postgraduate:public Graduate
{
public:
Postgraduate(char *gname,char *gnumber,char *guniversity,char *pdirection,char *ptutor):Graduate(gname,gnumber,0)
{
direction=new char[20];
strcpy(direction,pdirection);
tutor=new char[10];
strcpy(tutor,ptutor);
}
void print();
Postgraduate(const Postgraduate &k0); ~Postgraduate();
private:
char *direction;
char *tutor;
};

void Postgraduate::print()
{

cout<<" your direction:"<<direction<<endl;
cout<<" your tutor:"<<tutor<<endl;
}


Postgraduate::Postgraduate(const Postgraduate &k0)
{
setname(k0.getname);
number=new char[strlen(pnumber)+1];
strcpy(number,pnumber);

direction=new char[strlen(k0.direction)+1];
strcpy(direction,k0.direction);
tutor=new char[strlen(k0.tutor)+1];
strcpy(tutor,k0.tutor);

}
Postgraduate::~Postgraduate()
{
delete[] direction;
delete[] tutor;
}

void main()
{
char name[10];
char number[10];
char university[20];
char direction[20];
char tutor[10];
cout<<"please input your name:"<<endl;
cin>>name;
cout<<"please input your number:"<<endl;
cin>>number;
cout<<"please input your university:"<<endl;
cin>>university;
Graduate b(name,number,university);
b.print();

cout<<"please input your name:"<<endl;
cin>>name;
cout<<"please input your number:"<<endl;
cin>>number;
cout<<"please input your direction:"<<endl;
cin>>direction;
cout<<"please input your tutor:"<<endl;
cin>>tutor;
Postgraduate a(name,number,0,direction,tutor);
a.print();
}
错误如下：
:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(94) : error C2512: 'Graduate' : no appropriate default constructor available
G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(95) : error C2664: 'setname' : cannot convert parameter 1 from 'char *(void)' to 'char *'
There is no context in which this conversion is possible
G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(96) : error C2248: 'number' : cannot access private member declared in class 'Graduate'
G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(29) : see declaration of 'number'
G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(96) : error C2065: 'pnumber' : undeclared identifier
G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(97) : error C2248: 'number' : cannot access private member declared in class 'Graduate'
G:\大学课件\面向对象的程序设计\新建文件夹\c++实验2\Cpp3-1.cpp(29) : see declaration of 'number'
Error executing cl.exe.
大侠们帮帮忙哈！
lpf000 2009-05-23
  • 打赏
  • 举报
 回复
用VC6 就下个 谷歌金山词霸 随时翻译下嘛
arong1234 2009-05-23
  • 打赏
  • 举报
 回复
[Quote=引用 8 楼 hui135 的回复:]
5楼，我知道哪句英文什么意思，就是不知道怎么改？
[/Quote]

这里，你要求Graduate 有一个带两个参数的构造函数
Postgraduate(char *gname,char *gnumber,char *pdirection,char *ptutor):Graduate(gname,gnumber)

但是你的Graduate类的构造函数哪有带两个参数的？
lpf000 2009-05-23
  • 打赏
  • 举报
 回复
Graduate::Graduate(char *gname,char *gnumber,char *guniversity)
{
name=new char[10];
strcpy(name,gname);
number=new char[10];
strcpy(number,gnumber);
university=new char[20];
strcpy(university,guniversity);
}
那你的这个构造函数 动态分配的 时候要这样 university=new char[strlen(guniversity)+1];
hui135 2009-05-23
  • 打赏
  • 举报
 回复
5楼，我知道哪句英文什么意思，就是不知道怎么改？
lpf000 2009-05-23
  • 打赏
  • 举报
 回复
派生类中 有整个基类拷贝，是一个整体，不需要使用，使用默认值NULL嘛
Postgraduate(char *gname,char *gnumber,char *guniversity,char *pdirection,char *ptutor):Graduate(gname,gnumber,0)
hui135 2009-05-23
  • 打赏
  • 举报
 回复
问下2楼，还要添加哪些参数，最好把那句构造函数完整写出来哈！

lpf000 2009-05-23
  • 打赏
  • 举报
 回复
自己翻译一下那句英文都 该知道错误所在吧。。。
hui135 2009-05-23
  • 打赏
  • 举报
 回复
问下1楼：我不想继承guniversity得嘛，难道必须继承基类所有成员函数和数据成员吗
加载更多回复（3）
placement new
发信人: xgYao (小哥), 信区: CPlusPlus标  题: 请教个腾讯的考题发信站: 水木社区 (Mon Nov  5 14:48:30 2007), 站内class base{public:    virtual void f() {        cout&lt;&lt;"base::f()"&lt;&lt;endl;    }};class derived: public bas...
派生类中构造函数和print函数的调用时机（题目）
继承和派生在c++类和对象中是一个重要的知识体系，其中对于基类和派生类的构造函数以及同名函数的调用时机成为了一个难点（至少对博主而言是个大难点），特别是在基类中定义了虚函数的时候，我就更难判断了，所以本篇文章我将以复习资料中的一道题目为例子，带大家简要判断一下构造函数和同名函数在派生类中的调用时机。首先，C类继承B类，所以在调用C类构造函数之前，先会调用B类的构造函数，而在构建C类构造函数的时候，使用了初始化列表：B（i），所以先调用B类的有参构造函数。时，输出的是通过初始化列表初始化的基类。
关于c++派生类构造函数的思考
一道2011年阿里巴巴笔试题，主要考察派生类构造函数的执行过程 #include using namespace std; class A  {  public:      A()  {    cout     ~A() {    cout };    class B:public A  {  public:      B(A &a):_a(a)      {   
C++派生类的初始化顺序
重要的是要注意，即使你在派生类的初始化列表中显式地指定了基类和成员变量的初始化顺序，实际的初始化顺序还是按照它们在派生类定义中的声明顺序来决定的。：首先，按照基类在派生类中的声明顺序，从基类到基类依次调用它们的构造函数。：在基类的构造函数调用之后，派生类的成员变量按照它们在派生类定义中的声明顺序进行初始化。这包括所有的数据成员，无论它们是基本类型还是其他类的对象。：在所有基类和成员变量的构造函数调用完成之后，执行派生类构造函数的函数体。的构造函数，然后按照成员变量在派生类中的声明顺序调用。
C++ 派生类中的拷贝构造函数以及赋值运算符重载问题
由thinking in C++ 的一道题目引发的思考
C++ 语言

65,211

社区成员

250,514

社区内容

发帖
与我相关
我的任务
社区描述
C++ 语言相关问题讨论，技术干货分享，前沿动态等
c++ 技术论坛（原bbs）
社区管理员
  • C++ 语言社区
  • encoderlee
  • paschen
加入社区
  • 近7日
  • 近30日
  • 至今

加载中

查看更多榜单
社区公告
  1. 请不要发布与C++技术无关的贴子
  2. 请不要发布与技术无关的招聘、广告的帖子
  3. 请尽可能的描述清楚你的问题，如果涉及到代码请尽可能的格式化一下

试试用AI创作助手写篇文章吧

+ 用AI写文章