Linked List Problems

This is a discussion on Linked List Problems within the C++ Programming forums, part of the General Programming Boards category; Force of habit. Plus, there is no telling what system this code will run on. If its running on a ...

  1. #46
    Nor
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    Force of habit. Plus, there is no telling what system this code will run on.
    If its running on a new high powered pc then your right.
    If its running on a Wayne fuel dispenser, your wrong.
    Can not till you about an I-pod because i've never programed one. But i'm willing to bet a simple void pointer check will not crash the system as fast as processing a void pointer.
    c++ is not just for personal computers anymore.

    what linker error are you getting?
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  2. #47
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by Nor
    Force of habit. Plus, there is no telling what system this code will run on.
    If its running on a new high powered pc then your right.
    If its running on a Wayne fuel dispenser, your wrong.
    We are talking about a rule mandated by the C++ Standard.

    Quote Originally Posted by Nor
    Can not till you about an I-pod because i've never programed one. But i'm willing to bet a simple void pointer check will not crash the system as fast as processing a void pointer.
    I think you mean null pointer, not void pointer, but of course new is not guaranteed to return a null pointer if memory could not be allocated, unless the nothrow version of new is used.
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  3. #48
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    the linker error i am getting is
    undefined reference to 'operator<<(std:stream&, Song const&)'

  4. #49
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    Quote Originally Posted by cannsyl View Post
    the linker error i am getting is
    undefined reference to 'operator<<(std:stream&, Song const&)'
    So what does your function definition look like?

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  5. #50
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    my function definition is
    Code:
    ostream & operator << ( ostream & os, BobCatPod & i)
     {
          os << i.getTotalMemory();
          os  << i.getRemainingMemory();
          return os;
     }
    in bobcatpod.h
    and
    Code:
     ostream & operator << ( ostream & os, Song & s)
     {
          os << s.getTitle();
          os  << s.getArtist();
          os << s.getSize();
          return os;
     }
    song.h

  6. #51
    Use this: dudeomanodude's Avatar
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    I didn't look at the rest of this thread but:

    have you tried
    Code:
    std::ostream
    and (i just made the following mistake too):

    have you included <iostream> in the right place(s)?
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  7. #52
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    I tried adding the std:stream, but that didn't seem to be it.
    I don't know where you mean for me to put the <iostream> I do have it in my .h's

  8. #53
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by Nor View Post
    Force of habit. Plus, there is no telling what system this code will run on.
    While that's a valid point, it's better to assume standards compliance until proven otherwise, or unless you know up front that a targetted system isn't compliant. Even if you had to insert a new failure check at some future point, that shouldn't be so bad -- well designed software shouldn't be calling new from that many distinct places, anyway.

    If exceptions are available on your given platform set you should be using them, I guess is my point.
    Code:
    //try
    //{
    	if (a) do { f( b); } while(1);
    	else   do { f(!b); } while(1);
    //}

  9. #54
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    ok I am getting an error that says
    in function 'std:stream& operator<<(std:stream&, const Song&):
    invalid use of non-static data member 'Song::title'
    it is in line 15 of this code
    Code:
    //song.h
    #ifndef SONG_H
    #define SONG_H
    #include <stdlib.h>
    #include <iostream>
    #include <ostream>
    #include <string>
    //#include "BobCatPod.h"
    using namespace std;
    //std::ostream;
    
    class Song
    {
       private:
          string title;    //dynamic allocation
          string artist;
          int size;
       public:
          Song();
          Song(string , string , int ); // constructor
          void setSize(int s);
          int getSize(); // access or
          void setTitle (string t);
          string getTitle();
          void setArtist (string a);
          string getArtist();
          void addSong (int);
          friend ostream& operator<<(ostream & os, const Song &s)
          {
          os << title;
          os  << artist;
          os << size;
          return os;
          }
          bool operator==(const Song& lhs)
          {
               if (strcmp (artist, lhs.artist) == 0)
               {if (strcmp (title, lhs.title) ==0)
                {if (size == lhs.size)
                  return true;
                }
                }
                return false;
          }
          bool operator<(const Song& lhs)
          {
               if (artist < lhs.artist)
               { return true;
               }
               else if (artist > lhs.artist)
               {
                   return false;
               }
               else if (title < lhs.title)
               {
                    return true;
               }
               else if (title > lhs.title)
               {
                    return false;
               }
               else if (size < lhs.size)
               {
                    return true;
               }
               else
               {
                   return false;
               }
          }
      
    };
    #endif

  10. #55
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    ok I am getting an error that says
    Code:
    linker error undefined reference to  'Song::artist'
    but I am not sure where in the code it is...
    Code:
    //song.h
    #ifndef SONG_H
    #define SONG_H
    #include <stdlib.h>
    #include <iostream>
    #include <ostream>
    #include <string>
    //#include "BobCatPod.h"
    using namespace std;
    //std::ostream;
    
    class Song
    {
       private:
          string title;    //dynamic allocation
          string artist;
          int size;
       public:
          Song();
          Song(string , string , int ); // constructor
          void setSize(int s);
          int getSize(); // access or
          void setTitle (string t);
          string getTitle();
          void setArtist (string a);
          string getArtist();
          void addSong (int);
          friend ostream& operator<<(ostream & os, const Song &s)
          {
          os << title;
          os  << artist;
          os << size;
          return os;
          }
          bool operator==(const Song& lhs)
          {
               if (strcmp (artist, lhs.artist) == 0)
               {if (strcmp (title, lhs.title) ==0)
                {if (size == lhs.size)
                  return true;
                }
                }
                return false;
          }
          bool operator<(const Song& lhs)
          {
               if (artist < lhs.artist)
               { return true;
               }
               else if (artist > lhs.artist)
               {
                   return false;
               }
               else if (title < lhs.title)
               {
                    return true;
               }
               else if (title > lhs.title)
               {
                    return false;
               }
               else if (size < lhs.size)
               {
                    return true;
               }
               else
               {
                   return false;
               }
          }
      
    };
    #endif
    Last edited by cannsyl; 12-01-2008 at 02:27 PM. Reason: question changed

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