Constructor excercise problem
Hello,
i have a problem with an exercise:
the header is given:
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#ifndef HEADER_H_
#define HEADER_H_
class Cow {
private:
char name[20];
char * hobby;
double weight;
public:
Cow();
Cow(const char * nm, const char * ho, double wt);
Cow(const Cow &c);
~Cow();
Cow & operator=(const Cow & c);
void ShowCow() const; // display all cow data
};
#endif
|
Declaration of the function:
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#include <cstdlib>
#include "Header.h"
#include <iostream>
#include <cstring>
using std::cin;
using std::cout;
using std::endl;
static int num_strings;
Cow::Cow()
{
name[0]='\0';
hobby=new char[1];
hobby[0]='\0';
weight=0.0;
}
Cow::Cow(const char *nm, const char *ho, double wt)
{int len=0;;
int l=0;;
int length=0;
len=std::strlen(ho);
hobby=new char[len+1];
strcpy_s(hobby,len+1,ho);
l=std::strlen(nm);
strcpy_s(name,nm);
weight=wt;
num_strings++;
}
Cow::Cow(const Cow &c)
{
strcpy_s(name,c.name);
int length=(unsigned)strlen(c.hobby);
hobby=new char[length+1];
hobby=c.hobby;
weight=c.weight;
}
Cow::~Cow()
{
delete hobby;
delete name;
}
Cow&Cow::operator= (const Cow & c)
{
if(this==&c)
return *this;
delete [] hobby;
strcpy_s(name,sizeof (name),c.name);
hobby=c.hobby;
weight=c.weight;
return *this;
}
void Cow::ShowCow() const
{
cout<<"Output: "<<endl;
cout<<"nem: "<<name<<endl;
cout<<"hobby: "<<hobby<<endl;
cout<<"weight: "<<weight<<endl;
}
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main:
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#include <cstdlib>
#include "Header.h"
#include <iostream>
int main()
{using std::cin;
using std::cout;
using std::endl;
char na[]="cow";
char *hob="house";
double Gew=100.1;
Cow Kuh;
Cow Marta(na, hob, Gew);
Cow(Hansa);
Cow Tata=Hansa;
cout<<"Marta"<<endl;
Marta.ShowCow();
cout<<"Hansa"<<endl;
Hansa.ShowCow();
cout<<"Tata"<<endl;
Tata.ShowCow();
system("pause");
return 0;
}
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The code dont run and i can not find the errors.
Can someone help me please?
P.S: please with strcpy_s.
Thank you!
Last edited on
As far as I know,
strcpy_s() doesn’t exist in C++.
Hints:
Cow.h:
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#ifndef HEADER_COW_H
#define HEADER_COW_H
class Cow {
private:
char name[20];
char* hobby;
double weight;
public:
Cow();
Cow(const char* nm, const char* ho, double wt);
Cow(const Cow& c);
~Cow();
Cow& operator=(const Cow& c);
void ShowCow() const; // display all cow data
};
#endif // HEADER_COW_H
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Cow.cpp:
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#include "Cow.h"
#include <cstdlib>
#include <cstring>
#include <iostream>
Cow::Cow()
{
name[0] = '\0';
hobby = new char[1];
hobby[0] = '\0';
weight = 0.0;
}
Cow::Cow(const char* nm, const char* ho, double wt)
{
strncpy(name, nm, 20);
int len = std::strlen(ho);
hobby = new char[len+1];
strncpy(hobby, ho, len+1);
weight = wt;
}
Cow::Cow(const Cow& c)
{
strcpy(name, c.name);
int length = (unsigned)strlen(c.hobby);
hobby = new char[length+1];
strcpy(hobby, c.hobby);
weight = c.weight;
}
Cow::~Cow()
{
delete[] hobby;
}
Cow& Cow::operator= (const Cow& c)
{
if(this == &c) { return *this; }
strcpy(name, c.name);
delete[] hobby;
int length = (unsigned)strlen(c.hobby);
hobby = new char[length+1];
strcpy(hobby, c.hobby);
weight = c.weight;
return *this;
}
void Cow::ShowCow() const
{
std::cout << "Output: nem: " << name << "; hobby: " << hobby
<< "; weight: " << weight << '\n';
}
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main.cpp:
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#include "Cow.h"
#include <cstdlib>
#include <iostream>
#include <limits>
int main()
{
Cow Kuh;
char na[] = "cow";
char hob[] = "house";
double Gew = 100.1;
Cow Marta(na, hob, Gew);
std::cout << "Marta:\n";
Marta.ShowCow();
Cow Hansa(Marta);
std::cout << "Hansa:\n";
Hansa.ShowCow();
Cow Tata = Hansa;
std::cout << "Tata:\n";
Tata.ShowCow();
// system("pause"); <-- http://www.cplusplus.com/forum/beginner/1988/
std::cout << "\nPress ENTER to continue...\n";
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
return 0;
}
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Output:
Marta:
Output: nem: cow; hobby: house; weight: 100.1
Hansa:
Output: nem: cow; hobby: house; weight: 100.1
Tata:
Output: nem: cow; hobby: house; weight: 100.1
Press ENTER to continue... |
Thank you!
I do not understand why the name array do not have a destructor?
| why the name array do not have a destructor? |
You don't create 'name[]' by 'new', so it doesn't need to be explicitly deleted. It will die together with its class instance.
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