Programming Forums > Application Development > C

Pacer · May 24th, 2006, 9:33 PM

Hello,everybody.
I have no idea to rectify my error.
Could everyone helps me to solve it,thanks all.
I am a fresh man.Thanks again.

head file:

(Toggle Plain Text)

/* head file for double linked list */
/* Filename H1.h */

#include <stdio.h>
#include <stdlib.h>
#define LEN sizeof(linklist) /* Define the length of linked list */

typedef struct link
{
        char data;
        struct link * pre;
        struct link * next;
}linklist;            /* Defint structure of linked list */

main file:

(Toggle Plain Text)

/* double linked list main file */
/* Filename double.cpp */
#include "H1.h"

linklist * create(void)   /* Define the Function to create linked list*/
{
        linklist * head=NULL;
        linklist * p1,* p2;
        int i=2;              /* Define the sequence number */
        p1=(linklist *)malloc(LEN);
        head->next=p1;
        p1->pre=head;
        printf("Member[1] :");
        scanf("%c",&p1->data);
        
        if(p1!=NULL)
        {
                do
                {
                        p2=(linklist *)malloc(LEN);
                        printf("Member[%d] :",i);
                        scanf("%c",&p2->data);
                        p2->pre=p1;
                        p1->next=p2;
                        p1=p2;
                }while(p1->data!='$');
                p1->next=NULL;
                return head;
        }
}
/////////////////////////////////////////////////
void display(linklist * head) /* Define the function to display linked list */
{
        linklist * tem;
        int j=1;
        if((tem=head->next)!=NULL)
        {
                printf("\n");
                while(tem)
                {
                        printf("Member[%d] :",j++);
                        printf("%c",tem->data);
                }
        }
        else
        {
                printf("head node error, exit now!\n");
                exit(0);
        } 
}

//////////////////////////////////////////////////
void main()
{
        linklist * test_head;
        test_head=create();
        display(test_head);
}

The Dark · May 24th, 2006, 9:41 PM

You might want to let us know what the error is, we are not all mind-readers.

One thing that will cause a problem is this line near the top of create

(Toggle Plain Text)

        head->next=p1;

You have assigned the value of NULL to head and are then trying to dereference it, this will probably cause your program to shut down.

Note: I didn't look any further, there may be more problems, you need to give more information.

Pacer · May 24th, 2006, 9:57 PM

thank you Dark.
This is what I want to know.
I really didn't know where the error occured.But I have no more info about it.

The Dark · May 24th, 2006, 11:06 PM

You might not know where the error occurred, but you must know what sort of error it was. For example:
- Did the program not compile? (show the error messages)
- Did the program not link? (show the error messages)
- Did the program run but not produce the expected output? (show the output)
- Did the program run for a bit and then stop? (show any output or error)
- Did the program stop straight away? (show any error messages)
- Did the program connect to the net and buy stuff on ebay using your credit card? (show me what it bought, I might want some too).

Pacer · May 24th, 2006, 11:40 PM

Dark,I have completed.

(Toggle Plain Text)

/* linked list main file */
#include "H1.h"

linklist * create(linklist * point[2])   /* Define the Function to create linked list*/
{
        linklist * head,* tail;
        linklist * p1,* p2;
        int flag=0;
        int count=2;
        //linklist * point[2]; /* Deposit head and tail */
        p1=p2=(linklist *)malloc(LEN);
        printf("\nMember[1] :");
        scanf("%c",&p1->data);
        head=NULL;
        
        while(p1->data!='0')
        {
                flag++;
                if(flag==1)           /* the first node*/
                {
                        head=p1;
                        p1->pre=p1->next=NULL;
                }
                else                  /* other nodes except the first one */
                {
                        p2->next=p1;
                        p1->pre=p2;
                }
                p2=p1;
                p1=(linklist *)malloc(LEN);
                printf("Member[%d] :\n",count++);
                scanf("%c",&p1->data);
        }                         /* create nodes */

        p2->next=NULL;
        tail=p2;
        point[0]=head;
        point[1]=tail;
        return * point;
}
/////////////////////////////////////////////////
void dispAhead(linklist * head) /* Define the function to display linked list */
{
        linklist * tem;
        int j=1;
        if((tem=head)!=NULL)
        {
                printf("\n");
                while(tem)
                {
                        printf("Member[%d] :",j++);
                        printf("%c",tem->data);
                        tem=tem->next;
                }
        }
        else
        {
                printf("head node error, exit now!\n");
                exit(0);
        } 
}

//////////////////////////////////////////////////
void main()
{
        linklist * point[2];
        linklist * tem;
    tem=create(point);
        dispAhead(tem);

}

May 24th, 2006, 9:33 PM	#1
Pacer Newbie Join Date: May 2006 Posts: 4 Rep Power: 0	error of double linked list . Hello,everybody. I have no idea to rectify my error. Could everyone helps me to solve it,thanks all. I am a fresh man.Thanks again. head file: (Toggle Plain Text) /* head file for double linked list / / Filename H1.h / #include <stdio.h> #include <stdlib.h> #define LEN sizeof(linklist) / Define the length of linked list / typedef struct link { char data; struct link pre; struct link * next; }linklist; /* Defint structure of linked list / / head file for double linked list / / Filename H1.h / #include <stdio.h> #include <stdlib.h> #define LEN sizeof(linklist) / Define the length of linked list / typedef struct link { char data; struct link pre; struct link * next; }linklist; /* Defint structure of linked list / main file: (Toggle Plain Text) / double linked list main file / / Filename double.cpp / #include "H1.h" linklist create(void) /* Define the Function to create linked list/ { linklist head=NULL; linklist * p1,* p2; int i=2; /* Define the sequence number / p1=(linklist )malloc(LEN); head->next=p1; p1->pre=head; printf("Member[1] :"); scanf("%c",&p1->data); if(p1!=NULL) { do { p2=(linklist )malloc(LEN); printf("Member[%d] :",i); scanf("%c",&p2->data); p2->pre=p1; p1->next=p2; p1=p2; }while(p1->data!='$'); p1->next=NULL; return head; } } ///////////////////////////////////////////////// void display(linklist head) /* Define the function to display linked list / { linklist tem; int j=1; if((tem=head->next)!=NULL) { printf("\n"); while(tem) { printf("Member[%d] :",j++); printf("%c",tem->data); } } else { printf("head node error, exit now!\n"); exit(0); } } ////////////////////////////////////////////////// void main() { linklist * test_head; test_head=create(); display(test_head); } /* double linked list main file / / Filename double.cpp / #include "H1.h" linklist create(void) /* Define the Function to create linked list/ { linklist head=NULL; linklist * p1,* p2; int i=2; /* Define the sequence number / p1=(linklist )malloc(LEN); head->next=p1; p1->pre=head; printf("Member[1] :"); scanf("%c",&p1->data); if(p1!=NULL) { do { p2=(linklist )malloc(LEN); printf("Member[%d] :",i); scanf("%c",&p2->data); p2->pre=p1; p1->next=p2; p1=p2; }while(p1->data!='$'); p1->next=NULL; return head; } } ///////////////////////////////////////////////// void display(linklist head) /* Define the function to display linked list / { linklist tem; int j=1; if((tem=head->next)!=NULL) { printf("\n"); while(tem) { printf("Member[%d] :",j++); printf("%c",tem->data); } } else { printf("head node error, exit now!\n"); exit(0); } } ////////////////////////////////////////////////// void main() { linklist * test_head; test_head=create(); display(test_head); }

May 24th, 2006, 9:41 PM	#2
The Dark Expert Programmer Join Date: Jun 2005 Posts: 816 Rep Power: 4	You might want to let us know what the error is, we are not all mind-readers. One thing that will cause a problem is this line near the top of create (Toggle Plain Text) head->next=p1; head->next=p1; You have assigned the value of NULL to head and are then trying to dereference it, this will probably cause your program to shut down. Note: I didn't look any further, there may be more problems, you need to give more information.

May 24th, 2006, 11:40 PM	#5
Pacer Newbie Join Date: May 2006 Posts: 4 Rep Power: 0	Dark,I have completed. (Toggle Plain Text) /* linked list main file / #include "H1.h" linklist create(linklist * point[2]) /* Define the Function to create linked list/ { linklist head,* tail; linklist * p1,* p2; int flag=0; int count=2; //linklist * point[2]; /* Deposit head and tail / p1=p2=(linklist )malloc(LEN); printf("\nMember[1] :"); scanf("%c",&p1->data); head=NULL; while(p1->data!='0') { flag++; if(flag==1) /* the first node/ { head=p1; p1->pre=p1->next=NULL; } else / other nodes except the first one / { p2->next=p1; p1->pre=p2; } p2=p1; p1=(linklist )malloc(LEN); printf("Member[%d] :\n",count++); scanf("%c",&p1->data); } /* create nodes / p2->next=NULL; tail=p2; point[0]=head; point[1]=tail; return point; } ///////////////////////////////////////////////// void dispAhead(linklist * head) /* Define the function to display linked list / { linklist tem; int j=1; if((tem=head)!=NULL) { printf("\n"); while(tem) { printf("Member[%d] :",j++); printf("%c",tem->data); tem=tem->next; } } else { printf("head node error, exit now!\n"); exit(0); } } ////////////////////////////////////////////////// void main() { linklist * point[2]; linklist * tem; tem=create(point); dispAhead(tem); } /* linked list main file / #include "H1.h" linklist create(linklist * point[2]) /* Define the Function to create linked list/ { linklist head,* tail; linklist * p1,* p2; int flag=0; int count=2; //linklist * point[2]; /* Deposit head and tail / p1=p2=(linklist )malloc(LEN); printf("\nMember[1] :"); scanf("%c",&p1->data); head=NULL; while(p1->data!='0') { flag++; if(flag==1) /* the first node/ { head=p1; p1->pre=p1->next=NULL; } else / other nodes except the first one / { p2->next=p1; p1->pre=p2; } p2=p1; p1=(linklist )malloc(LEN); printf("Member[%d] :\n",count++); scanf("%c",&p1->data); } /* create nodes / p2->next=NULL; tail=p2; point[0]=head; point[1]=tail; return point; } ///////////////////////////////////////////////// void dispAhead(linklist * head) /* Define the function to display linked list / { linklist tem; int j=1; if((tem=head)!=NULL) { printf("\n"); while(tem) { printf("Member[%d] :",j++); printf("%c",tem->data); tem=tem->next; } } else { printf("head node error, exit now!\n"); exit(0); } } ////////////////////////////////////////////////// void main() { linklist * point[2]; linklist * tem; tem=create(point); dispAhead(tem); }

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May 24th, 2006, 9:57 PM	#3
Pacer Newbie Join Date: May 2006 Posts: 4 Rep Power: 0	thank you Dark. This is what I want to know. I really didn't know where the error occured.But I have no more info about it.

May 24th, 2006, 11:06 PM	#4
The Dark Expert Programmer Join Date: Jun 2005 Posts: 816 Rep Power: 4	You might not know where the error occurred, but you must know what sort of error it was. For example: - Did the program not compile? (show the error messages) - Did the program not link? (show the error messages) - Did the program run but not produce the expected output? (show the output) - Did the program run for a bit and then stop? (show any output or error) - Did the program stop straight away? (show any error messages) - Did the program connect to the net and buy stuff on ebay using your credit card? (show me what it bought, I might want some too).

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Programming Forums > Application Development > C

error of double linked list .