Small code works on VS6 crash on VS2005 WHY???

This is a discussion on Small code works on VS6 crash on VS2005 WHY??? within the C Programming forums, part of the General Programming Boards category; This code runs without problems on VS6, but crashes on VS2005 (I've just started to use VS2005) Please WHY?? Code: ...

  1. #1
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    Small code works on VS6 crash on VS2005 WHY???

    This code runs without problems on VS6, but crashes on VS2005 (I've just started to use VS2005)
    Please WHY??

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    
    typedef struct
    {
    	int iCode;
    	char *pName;
    	double dPrice;
    } Products;
    
    struct Node
    {
    	Products products;
    	struct Node *pNext;
    	struct Node *pPreview;
    };
    
    void AddNodeHead (struct Node **pNode)
    {
    	struct Node *pTemp;
    	puts("Adding node");
    	pTemp=malloc(sizeof(Products));
    	
    	puts("Done!");
    
    	if (pTemp==NULL)
    	{
    		puts("Failed to allocate!");
    		// Delete All
    		exit(1);
    	}
    
    	pTemp->pNext=*pNode;
    	pTemp->pPreview=NULL;
    
    	if (*pNode)
    		(*pNode)->pPreview=pTemp;
    
    	*pNode=pTemp;
    }
    
    
    int main ( void )
    {
    	struct Node *pHead=NULL;
    	int i;
    
    	for (i=0;i<3;++i)
    		AddNodeHead(&pHead);
    	return 0;
    }

  2. #2
    Registered User hk_mp5kpdw's Avatar
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    Code:
    struct Node *pTemp;
    puts("Adding node");
    pTemp=malloc(sizeof(Products));
    "Owners of dogs will have noticed that, if you provide them with food and water and shelter and affection, they will think you are god. Whereas owners of cats are compelled to realize that, if you provide them with food and water and shelter and affection, they draw the conclusion that they are gods."
    -Christopher Hitchens

  3. #3
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    Thank you hk_mp5kpdw.
    Howerver I still can't understand what I did wrong...

  4. #4
    C++まいる!Cをこわせ! Elysia's Avatar
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    The size of a Node structure is not the same as the size of a Products structure. You got undefined behavior.
    You allocate too little space to hold your Node structure.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

  5. #5
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    I can't believe I did such a stupied mistake.

    Thank you guys!

  6. #6
    CSharpener vart's Avatar
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    Quote Originally Posted by salvadoravi View Post
    I can't believe I did such a stupied mistake.

    Thank you guys!
    to avoid such mistakes use the working always patter

    pObj = malloc (sizeof *pObj);
    The first 90% of a project takes 90% of the time,
    the last 10% takes the other 90% of the time.

  7. #7
    Registered User aLiNuSh's Avatar
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    Quote Originally Posted by vart View Post
    to avoid such mistakes use the working always patter

    pObj = malloc (sizeof *pObj);
    Shouldn't this, dereferencing an unallocated pointer, cause undefined behavior?

  8. #8
    C++まいる!Cをこわせ! Elysia's Avatar
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    Not with the use of sizeof.
    Sizeof doesn't dereference the pointer, but merely evaluates the type.
    Quote Originally Posted by Adak View Post
    io.h certainly IS included in some modern compilers. It is no longer part of the standard for C, but it is nevertheless, included in the very latest Pelles C versions.
    Quote Originally Posted by Salem View Post
    You mean it's included as a crutch to help ancient programmers limp along without them having to relearn too much.

    Outside of your DOS world, your header file is meaningless.

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