DAMAGE: after Normal block (#42) at 0x00430160

[dumbterminal]

Hi all, i am trying to traverse through a folder and print its contents, but however getting rudely crashed, has it got anything to do with the queue i have tried to implement ?? Thanx in advance :D

#include <stdio.h>
#include <windows.h>
#include <string.h>
#include <stdlib.h>


class queue{
	private:
		struct item{
			char src[255] ;
			struct item *next ;
		} ;
		typedef struct item ITEM ;

		ITEM* head_ptr ;
		ITEM* tail_ptr ;
	
	public:
		queue() ;
		~queue() ;
		int empty() ;
		void front(char *src) ;
		void pop() ;
		void push(char *src) ;
		
} ;

queue::queue()
{
	head_ptr = NULL ;
	tail_ptr = NULL ;
}

void queue::push(char *src)
{
	ITEM* temp = (ITEM*)malloc(sizeof(temp)) ;
	strcpy(temp->src, src) ;
	temp->next = NULL ;

	if (head_ptr == NULL){
		head_ptr = temp ;
		//tail_ptr = temp ;
	}else{
		tail_ptr->next = temp ;
		
	}
	tail_ptr = temp ;
	
}

void queue::pop()
{
	ITEM* temp = NULL ;
	temp = head_ptr ;
	head_ptr = head_ptr->next ;
	if (head_ptr == NULL){
		tail_ptr = NULL ;
	}else{
		head_ptr = head_ptr->next ;
	}
	free(temp) ;
}

int queue::empty()
{
	return (head_ptr == NULL) ;
}

void queue::front(char *src)
{
	if (head_ptr) strcpy(src, head_ptr->src) ;
}

queue::~queue()
{
	ITEM* temp = NULL ;
	while (head_ptr->next){
		temp = head_ptr ;
		head_ptr = head_ptr->next ;
		free(temp) ;
	}
	free(head_ptr) ;
	head_ptr = NULL ;
	tail_ptr = NULL ;
}

struct OPERATIONDESC{
	char src[255] ;
	char dest[255] ;
} ;

void folder_traverse(void *id)
{
	char level[255] ;
	char temp[255] ;
	char temp_1[255] ;

	HANDLE h ;
	WIN32_FIND_DATA info ;

	struct OPERATIONDESC* op = (struct OPERATIONDESC*)id ;
	queue q ;
	
	q.push(op->src) ;

	while (!q.empty()){
		q.front(level) ;
		q.pop() ;
		
		strcpy(temp, level) ;
		strcat(temp, "\\*.*") ;

		h = FindFirstFile(temp, &info) ;
		do{
			if (!strcmp(info.cFileName, ".")) continue ;
			if (!strcmp(info.cFileName, "..")) continue ;
			
			strcpy(temp_1, level) ;
			strcat(temp_1, "\\") ;
			strcat(temp_1, info.cFileName) ;

			if(info.dwFileAttributes == FILE_ATTRIBUTE_DIRECTORY){
				q.push(temp_1) ;
			}else{
				printf("%s\n", temp_1) ;
			}
		}while (FindNextFile(h, &info)) ;



	}

}
int main()
{
	struct OPERATIONDESC d ;
	strcpy(d.src, "c:\\test") ;
	folder_traverse((void*)&d) ;
	return 0 ;


}

[guestgulkan]

void queue::push(char *src)
{
	ITEM* temp = (ITEM*)malloc(sizeof(temp)) ;//<<==/ERROR here - 
	strcpy(temp->src, src) ;
	temp->next = NULL ;

        ....

[dumbterminal]

Thanx :D. I have changed that and still getting crashed. What could it be, running the debugger i see it is crashing after popping twice. ther's got to b a catch smwhere. hoping ur response. :D

[guestgulkan]

OK I assume that you changed it to this:
ITEM* temp = (ITEM*)malloc(sizeof(ITEM)) ;


This bit doesn't look right to me:

void queue::pop()
{
	ITEM* temp = NULL ;
	temp = head_ptr ;
	head_ptr = head_ptr->next ;
	if (head_ptr == NULL){
		tail_ptr = NULL ;
	}else{
		head_ptr = head_ptr->next ;//<<===== ?????
	}
	free(temp) ;
}

I believe it is causing a problem later on with the destructor because head_ptr is NULL

queue::~queue()
{
	ITEM* temp = NULL ;
	while (head_ptr->next){
		temp = head_ptr ;
		head_ptr = head_ptr->next ;
		free(temp) ;
	}
	free(head_ptr) ; 
	head_ptr = NULL ;
	tail_ptr = NULL ;
}

[dumbterminal]

Oh thank you very much. Actually i have been skipping my data structure classes a lot (thought there's always STL). But now at the end of the year suffering a lot as teachers won't allow STL in the projects. :D. Thanx again you have been very helpful indeed.