RE: [Dev-C++] newbie questions without answer

[Ioannis V. <no...@ho...>]

 <http://run.to/noicys>=20
-----Original Message-----
From: dev...@li...
[mailto:dev...@li...] On Behalf Of Carlos
Garc=EDa del Monte
Sent: Sunday, August 11, 2002 9:53 PM
To: dev-cpp-users-list
Subject: Re: [Dev-C++] newbie questions without answer



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The code post is only a part, talking about the files he gave (perhaps
you didn't receive the files?). =20
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Nope, i did not receive any attachment. Thanks for the info. Now lets
answer to the original poster:

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I wrote principally for him, but as you want see all, here is the code:=20

The code for the struct thing (newbiequestion.cpp) is:=20
#include <iostream>=20
#include <stdlib.h>=20
#include <string.h>=20


struct date{=20
   int month;=20
   int day;=20
   int year;=20
};=20


struct employ{=20
  char *first;=20
  char *second;=20
  date eyear;  /*i want to use a reference to the year in the first
struct=20
               but then i get an error message from the compiler since i
didn't=20
 =20

You can use a reference provided that you have a date object and a
constructor for struct employ.=20
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E.g.:
=20
struct date{=20
   int month;=20
   int day;=20
   int year;=20
};=20
=20
struct employ{=20
  char *first;=20
  char *second;=20
  int &eyear;
=20
  employ(char *f, char *s, int &y):first(f), second(s), eyear(y)
  {}
};
=20
int main()
{
  date d;
 =20
  employ e(new char, new char, d.year);
}
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Just for the record, i do not like the approach you are using, it is too
C-style.
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=20

=20
};=20
int main()=20
{=20
      date d;=20
      employ e;=20
      d.day=3D30;=20
      d.month=3D8;=20
      d.year=3D1982;=20
      e.eyear =3D d;=20
      e.first=3Dnew char [strlen("senem")];   // a way of doing this
shortly?? =20

=20

Using a constructor and standard library facilities like std::string. If
you do not use a reference mentioned previously, you could use an
initializer list but it is too naked.

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=20
      e.second=3Dnew char [strlen("beken")];=20
      e.first=3D"senem";=20
      e.second=3D"beken";=20

      cout<<e.first<<" "<<e.second<<endl;=20
      cout<<"birthday:\n"=20
      <<e.eyear.day<<"/"<<e.eyear.month<<"/"<<e.eyear.year<<endl;=20
      system("PAUSE");=20
      return 0;=20
}=20


Another is the stringclas.cpp file which source is:=20


#include <iostream>=20
#include <stdlib.h>=20
#include <cassert>=20
#include <string.h>=20
#include <iomanip.h>=20


class string{=20
 friend ostream &operator<<(ostream &,const string&);=20
 friend istream &operator>>(istream &,string&);=20
public:=20
 string(const char * =3D"");=20


 string(const string &);=20
 ~string();=20
 const string &operator=3D(const string &);=20
 const string &operator+=3D(const string &);=20
 bool operator!()const;=20
 bool operator=3D=3D(const string&)const;=20
 bool operator<(const string&)const;=20
 bool operator!=3D(const string& right)const=20
 {return !(*this=3D=3Dright);}=20
 bool operator>(const string& right)const=20
    {return (right<*this);}=20
 bool operator<=3D(const string& right)const=20
    {return !(right<*this);}=20
 bool operator>=3D(const string& right)const=20
    {return !(*this<right);}=20
 char &operator[](int);=20
 const char &operator[](int)const;=20
 string operator()(int,int);=20
 int getlength()const;=20
private:=20
 int length;=20
 char * sptr;=20
 void setstring(const char*);=20
};=20


string::string(const char *s):length(strlen(s)){=20
  cout<<"conversion constructor :"<<s<<"\n";=20
  setstring(s);=20
}=20


string::string(const string&copy):length(copy.length){=20
  cout<<"copy constructor: "<<copy.sptr<<"\n";=20
  setstring(copy.sptr);=20
}=20


string::~string(){=20
  cout<<"destructor: "<<sptr<<"\n";=20
  delete[]sptr;=20
}=20


const string &string::operator=3D(const string &right){  //burda nie ref
var??=20
  cout<<"operator=3D called\n";=20


  if(&right!=3Dthis){=20
   delete[]sptr;=20
   length=3Dright.length;=20
   setstring(right.sptr);=20
  }=20
  else=20
   cout<<"attempted assignment of a string to itself\n";=20


   return *this;=20
}=20


const string &string::operator+=3D(const string &right){=20


char *string1=3Dnew char[length+right.length+1];    ///DON'T MODIFY THE
SIZE=20
strcpy(string1,sptr);    /* i tried to change this part a little=20
                         so that the first string is not modified,but
then=20
                         the program started to terminate abnormally=20
                         and i have absolute no idea what i did  wrong!!

                         here is the original: =20

=20

What kind of abnormal termination. assert()?=20

                          char *tempptr=3Dsptr;=20
                          lenght+=3Dright.length;=20
                          sptr=3Dnew char [length+1];=20
                          assert(sptr!=3D0);=20
                          strcpy(sptr,tempptr);=20
                          strcat(sptr,right.ptr);=20
                          delete[]tempptr;=20
                          return *this;*/ =20

=20

=20
I must mention that C++ provides already a string type defined in
<string>. So why do you bother? :)=20

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Ioannis

* Ioannis Vranos
* Programming pages: http://www.noicys.cjb.net
<http://www.noicys.cjb.net/>=20
* Alternative URL: http://run.to/noicys
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