Thread: issue with linked list !!IMPORTANT

Guys this is the error that the windows crash dialogue box is showing

Problem signature: Problem Event Name: APPCRASH
Application Name: ntest11.exe
Application Version: 0.0.0.0
Application Timestamp: 51c08bb6
Fault Module Name: ntest11.exe
Fault Module Version: 0.0.0.0
Fault Module Timestamp: 51c08bb6
Exception Code: c0000005
Exception Offset: 00001372
OS Version: 6.1.7600.2.0.0.256.1
Locale ID: 16393
Additional Information 1: 0a9e
Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
Additional Information 3: 0a9e
Additional Information 4: 0a9e372d3b4ad19135b953a78882e789


Read our privacy statement online:
Windows 7 Privacy Statement - Microsoft Windows


If the online privacy statement is not available, please read our privacy statement offline:
C:\Windows\system32\en-US\erofflps.txt

okay i'll try

@jim i noted all your points and increased my errors the last error i asked i rectified it but there is one erro m not able to solve

D:\softwareinstall\Codeblocks workspace\testprogs\ntest11.c|21|warning: 'trys' is used uninitialized in this function [-Wuninitialized]|

i did initialised trys as *trys abuv in my code.

errors=*warnings

i did initialised trys as *trys abuv in my code.

Obviously not or your compiler wouldn't be telling you about the issue. But for a better answer you'll need to post your current code.

Jim

@jim

Code:

#include<stdio.h>#include<strings.h>
#include<stdlib.h>
#include<malloc.h>


struct node
{
    int data;
    struct node *next;
};


typedef struct node link;


link create_link(link *r);


int main()
{
    link *trys,*k;
    int i,j,num;


    k=trys;


    printf("Enter the Number  data\n");
    scanf("%d",&num);
    trys->data=num;
    trys->next=NULL;
    p: printf("\nDo you want to add more numbers?(Y=1/N=0)");
    scanf("%d",&i);
    if(i==1)
    {
        for(j=0;trys->next==NULL;j++)
                trys=trys->next;
        create_link(trys);
        {
            trys=k;
            for(j=0;trys->next==NULL;j++)
                trys=trys->next;
            printf("\nEnter the next Number data\n");
            scanf("%d",&num);
            trys->data=num;
        }
        trys=k;
        goto p;
    }
    else
    {
        printf("\nNumber dat entered by you is:\n");
        for(j=0;trys->next==NULL;j++)
        {
            printf("%d\n",trys->data);
        }
    }
    return 0;
}


link create_link(link *r)
{
    link *addon;


    addon=malloc(sizeof(link));
    r->next=addon;
    addon->next=NULL;
    return *r;
}

Look at the following snippet:

Code:

    link *trys,*k;
    int i,j,num;


    k=trys;

Where have you initialized trys?

Jim

okay okay please correct me is *trys not an initialisation for trys as it is for k in the link datatype and how will i initialise an address as trys is actually an address.

okay okay please correct me is *trys not an initialisation for trys as it is for k in the link datatype and how will i initialise an address as trys is actually an address.

The warning is about *trys. You have not initialized this variable before you try to initialize k. At this point you don't know where *trys is pointing.

You need to either allocate memory for this uninitialized pointer (*trys) or assign the pointer to a valid memory location.

Jim

@jim can you explain with an example

okay got your point jim corrected it by a malloc.

i'm also beginner to c/ds & this forum, can somebody please comment on this, if i'm wrong, Thanks in advance.

Originally Posted by Amitesh93

@jim

Code:

#include<stdio.h>#include<strings.h>
#include<stdlib.h>
#include<malloc.h>


struct node
{
    int data;
    struct node *next;
};


typedef struct node link;


link create_link(link *r);


int main()
{
    link *trys,*k;
    int i,j,num;


    k=trys;

    trys = (link *) malloc (sizeof(link)); 
    printf("Enter the Number  data\n");
    scanf("%d",&num);
    trys->data=num;   //previously crash was happened here, now memory is allocated so here crash wont happen.
    trys->next=NULL;
    p: printf("\nDo you want to add more numbers?(Y=1/N=0)");
    scanf("%d",&i);
    if(i==1)
    {
/*        for(j=0;trys->next==NULL;j++)   //this also wrong, you have to try until u reach null  
                trys=trys->next;
   */
         for(j=0;trys->next!=NULL;j++) 
               trys=trys->next;
        k = create_link(&trys); // k points to the allocated memory
        {
//         trys=k;     // here you are assigning k to trys, as of your code, memory is not allocated for trys, again while accessing trys may crash.
//         for(j=0;trys->next==NULL;j++)   
//             trys=trys->next;
            printf("\nEnter the next Number data\n");
            scanf("%d",&num);
            trys->data=num;
        }
       // trys=k;
        goto p;
    }
    else
    {
        printf("\nNumber dat entered by you is:\n");
        //for(j=0;trys->next==NULL;j++)
        for(j=0;trys->next!=NULL;j++)
        {
            printf("%d\n",trys->data);
        }
    }
    return 0;
}


link create_link(link **r)
{
    link *addon;


    addon=malloc(sizeof(link));
    *r->next=addon;
    addon->next=NULL;
    return addon;
}

@pappu i actually corected the == to != operator it was just for testng dat i did but @ line 57 do u want me to use ==