link list

[coderire]

Hi i am trying to make a link list.The data to the link list will be added from the command line . example of a command line will --- I 45 here 45 is the data to be added.(time)

the following is my working

#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>

// get include from current directory.

#define UINT unsigned int
using namespace std;

struct item
{ UINT time ; // time in tics which is used to order the list.
UINT id ; // penguin id number.
UINT event ; // event this item describes.
struct item *next ; // pointer to next item in list.
} ;

struct item *head_ptr ;
struct item *work_ptr ;


int main(int argc, char *argv[])
{


for(int i=1; i<argc; i++)
{
if (!strcmp(argv[i],"I"))
{

work_ptr=head_ptr;
head_ptr=(item*)malloc(sizeof(struct item));

strcpy((char*)head_ptr->time ,(char*)argv [i+1] ) ;


cout << head_ptr ->time << endl;

head_ptr -> next = work_ptr;
}


return 0;
}

but at the strcpy((char*)head_ptr->time ,(char*)argv [i+1] ) ; i get SEGMENTATION FAULT i dont know whats wrong with my code please help

[Bibek Subedi]

can you please write the code inside code tag. its very difficult to read the code

[Jikax]

Maybe use more braces... And make it a pointer... Not really sure... (char*)&(head_ptr->time)

[coderire]

struct item
{ UINT time ; // time in tics which is used to order the list.
UINT id ; // penguin id number.
UINT event ; // event this item describes.
struct item *next ; // pointer to next item in list.
} ;

struct item *head_ptr ;
struct item *work_ptr ;


int main(int argc, char *argv[])
{


for(int i=1; i<argc; i++)
{
if (!strcmp(argv[i],"I"))
{

work_ptr=head_ptr;
head_ptr=(item*)malloc(sizeof(struct item));

strcpy((char*)&(head_ptr->time) ,(char*)&(argv [i+1]) ) ;


cout << head_ptr ->time << endl;

head_ptr -> next = work_ptr;
}

i get some random number for cout<< head_ptr->time when i did that

[Jikax]

It looks like you want to concert a string to a integer... Use atoi to do that:

head_ptr->time = atoi(argv[a+1]);

[coderire]

no i want to copy the command line parameter and store it in the link list

[Jikax]

Ah.. I see... Now you have only 1 value but you plan on filling the complete struct? Do you want to save the number 45 or the representation of the characters '4' and '5'?

[coderire]

number 45

[Jikax]

Then you should use atoi...

head_ptr->time = atoi(argv[a+1]);

[coderire]

yeah that worked thanks