adding to linked list

This is a discussion on adding to linked list within the C Programming forums, part of the General Programming Boards category; I keep getting a program crash whenever I am adding an element to my linked list but I just can ...

  1. #1
    Registered User camel-man's Avatar
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    adding to linked list

    I keep getting a program crash whenever I am adding an element to my linked list but I just can not seem to figure out what is going wrong I think it might have to do with my anchor node.



    Code:
    typedef char NodeItemT;
    
    typedef struct NodeT
    {
    	NodeItemT info;
    	struct NodeT *next;
    } NodeT;
    
    typedef struct VectorT
    {
    	NodeT *anchor;
    } VectorT;
    
    
    VectorT *newVector();
    void addElement(VectorT *vector, NodeItemT item);
    
    
    int main()
    {
        VectorT *head;
        head=newVector();
        
        addElement(head,'A');
        
        
        
    getch();
    return 0;    
    }
    
    VectorT *newVector()
    {
     VectorT *vector;
     vector= (VectorT*) malloc(sizeof(VectorT));
     vector->anchor=(NodeT*)malloc(sizeof(NodeT));
     vector->anchor=NULL;;        
     return vector;       
    }
    
    
    void addElement(VectorT *vector, NodeItemT item)
    {
        NodeT *temp;
        temp=(NodeT*)malloc(sizeof(NodeT));
        temp=vector->anchor; 
        while(temp->next!=NULL)
        {
        temp=temp->next;
        }
        
        NodeT *temp1;
        temp1=(NodeT*)malloc(sizeof(NodeT));
        temp1->info=item;
        temp1->next=NULL;
        temp->next=temp1;
         
       
    }

  2. #2
    Just a pushpin. bernt's Avatar
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    I think it might have to do with my anchor node.
    Code:
    VectorT *newVector()
    {
     VectorT *vector;
     vector= (VectorT*) malloc(sizeof(VectorT));
     vector->anchor=(NodeT*)malloc(sizeof(NodeT));
     vector->anchor=NULL;;     //<---------
     return vector;      
    }
    Consider this post signed

  3. #3
    Registered User camel-man's Avatar
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    yeah that doubly semicolon was a typo but it still crashes whenever I add an element


    Code:
    typedef char NodeItemT;
    
    typedef struct NodeT
    {
    	NodeItemT info;
    	struct NodeT *next;
    } NodeT;
    
    typedef struct VectorT
    {
    	NodeT *anchor;
    } VectorT;
    
    
    VectorT *newVector();
    void addElement(VectorT *vector, NodeItemT item);
    NodeItemT get(const VectorT *vector,int index);
    
    
    int main()
    {
        VectorT *head;
        head=newVector();
        
        addElement(head,'A');
        addElement(head,'B');
        addElement(head,'C');
        NodeItemT retrieve;
        retrieve=get(head,0);
        printf("%c\n",retrieve);
        
        
        
    getch();
    return 0;    
    }
    
    
    VectorT *newVector()
    {
     VectorT *vector;
     vector= (VectorT*) malloc(sizeof(VectorT));
     vector->anchor=(NodeT*)malloc(sizeof(NodeT));  
     vector->anchor->next=NULL;      
     return vector;       
    }
    
    
    void addElement(VectorT *vector, NodeItemT item)
    {
         
        if(vector->anchor->next==NULL)
        vector->anchor->info=item;
        
        else
        {
        NodeT *temp;
        temp=(NodeT*)malloc(sizeof(NodeT));
        temp=vector->anchor; 
        while(temp->next!=NULL)
        {
        temp=temp->next;
        }
        
        NodeT *temp1;
        temp1=(NodeT*)malloc(sizeof(NodeT));
        temp1->info=item;
        temp1->next=NULL;
        temp->next=temp1;
        }
      
    }
    
    
    NodeItemT get(const VectorT *vector,int index)
    {
         int i;
         NodeT *getItem;
         getItem=(NodeT*)malloc(sizeof(NodeT));
         getItem=vector->anchor;
         for(i=0;i<index;i++)
         {
           getItem=getItem->next;                 
         }    
         return getItem->info; 
              
                
    }
    Last edited by camel-man; 10-08-2011 at 05:55 PM.

  4. #4
    Algorithm Dissector iMalc's Avatar
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    As a programmer you're going to need to start looking into debugging this kind of thing. Rather than doing either the "throw your arms up in the air" approach or the "spend hours staring at the code hoping something jumps out at you" approach, it's probably time to start learning to use a debugger. You'll be glad you did.
    Now, what development environment do you have?

    Oh and FYI, you could have 100 secmicolons on that line and it wouldn't make a difference.

    Lastly, make sure you initialise stuff, even dynamically allocated stuff.
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  5. #5
    ATH0 quzah's Avatar
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    Why does newVector make a new node too? Also, if you actually included the right headers, you wouldn't be forced to typecast every return from malloc all the time. Void pointers don't need casts to be assigned to things. Why would addelement ever encounter a vector without an anchor, since when you make a new vector through your function, it automatically makes a node? I suppose it's just good error checking - but your new vector function shouldn't be adding nodes in my opinion. You are over complicating this a bit.


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  6. #6
    Registered User camel-man's Avatar
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    I am using Dev C++ and I will have too look into debugging im not sure quite what it is but if it can help me with these run time errors and segmentation faults then I am all for it.

  7. #7
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    Camel-Man.... Dev C++ is abandonware (has been for at least 5 years now) and the compiler that comes with it is about 3 generations old.

    I'm thinking it's time to update to C-99 standards... Pelles C ... build 32 or 64 bit executables, full set of resource tools and editors, full set of windows headers (current), complete documentation... and free.

  8. #8
    Registered User camel-man's Avatar
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    Quote Originally Posted by CommonTater View Post
    Camel-Man.... Dev C++ is abandonware (has been for at least 5 years now) and the compiler that comes with it is about 3 generations old.

    I'm thinking it's time to update to C-99 standards... Pelles C ... build 32 or 64 bit executables, full set of resource tools and editors, full set of windows headers (current), complete documentation... and free.
    Will C-99 be more sufficient and accurate to GCC then dev-C++ is to gcc?

  9. #9
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by camel-man
    Will C-99 be more sufficient and accurate to GCC then dev-C++ is to gcc?
    What do you mean?
    C + C++ Compiler: MinGW port of GCC
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    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  10. #10
    Registered User camel-man's Avatar
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    Well I just noticed whenever I would transfer code from Dev_c++ to GCC I would have errors alot, I was just wondering If this new compiler is better

  11. #11
    and the hat of int overfl Salem's Avatar
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    dev-c++ is an IDE, not a compiler.

    It comes with GCC. The only difference being it is a version of GCC that is about 5 years older than the version of GCC that comes with say the latest version of code::blocks.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
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  12. #12
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by camel-man
    Well I just noticed whenever I would transfer code from Dev_c++ to GCC I would have errors alot
    Dev-C++ comes with gcc by default, so that begs the question of what you mean by "transfer code from Dev_c++ to GCC".

    Quote Originally Posted by camel-man
    I was just wondering If this new compiler is better
    It will probably be worse, if the compiler that comes with Dev-C++ is your measure of "best". As CommonTater has noted, that compiler is not as updated.
    C + C++ Compiler: MinGW port of GCC
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  13. #13
    Registered User camel-man's Avatar
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    Quote Originally Posted by laserlight View Post
    Dev-C++ comes with gcc by default, so that begs the question of what you mean by "transfer code from Dev_c++ to GCC".


    It will probably be worse, if the compiler that comes with Dev-C++ is your measure of "best". As CommonTater has noted, that compiler is not as updated.
    So do you reccomend pelles C-99 over Dev-C++?

  14. #14
    Registered User whiteflags's Avatar
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    I realize the might come off as mean, but:
    C99 is a language standard, meant to be followed by compiler vendors.
    Pelles C is an IDE and an implementation of C99.

    If you can't write C, switching compilers because its C99 is not going to magically make your code better and I would wager that there are going to be the same amount of errors. I'm not sure what you're expecting.

  15. #15
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    There is a newer version for Dev-C++

    Orwell's Engine: Dev-C++ 4.9.9.3 released

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