Thread: issue with linked list !!IMPORTANT

Actually i am trying to learn data structures and came to linked list ,i tried to make a program and according to my knowledge its correct as the compiler(code::blocks) is showing 0 error 0 warnings, but still when i run my compiled program it crashes and stops execution don't kno why? pls help in the matter
THE CODE IS:

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);


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


    k=trys;


    printf("Enter the Number  data\n");
    scanf("%d",trys->data);
    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",trys->data);
        }
        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);
        }
    }
}


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


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

When I compile your code using my IDE (Code::Blocks) I get the following errors and warnings. Maybe you should increase the number of warnings being generated.

main.c|20|error: return type defaults to ‘int’|
main.c||In function ‘main’:|
main.c|30|warning: format ‘%d’ expects argument of type ‘int *’, but argument 2 has type ‘int’ [-Wformat]|
main.c|45|warning: format ‘%d’ expects argument of type ‘int *’, but argument 2 has type ‘int’ [-Wformat]|
main.c|23|warning: unused variable ‘p’ [-Wunused-variable]|
main.c||In function ‘create_link’:|
main.c|69|warning: control reaches end of non-void function [-Wreturn-type]|
||=== Build finished: 1 errors, 4 warnings ===|

Also you need to stop using goto, investigate one of the other more acceptable loop constructs.

Jim

Actually i am trying to learn data structures and came to linked list ,i tried to make a program and according to my knowledge its correct as the compiler(code::blocks) is showing 0 error 0 warnings, but still when i run my compiled program it crashes and stops execution don't kno why? pls help in the matter
THE CODE IS:

Code:

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);


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


    k=trys;


    printf("Enter the Number  data\n");
    scanf("%d",trys->data);
    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",trys->data);
        }
        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);
        }
    }
}


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


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

@jim can please tell me what the error means and how to send a struct data for scanning? bcz in the book they were scanning like dis only.

@vart how to send the struct data then?

p->data

please tell me what the error means

Which error message don't you understand, there's five separate errors?

Jim

@vart are you asking me how to declare a pointer? or how to send a pointer

@jim error is one and all the rest warnings also can't get them.

First they all need to be considered errors. Those "warnings" are errors in disguise and are probably part of the problem.

So you don't understand this error?

main.c|20|error: return type defaults to ‘int’|

You really need to start learning to read the error messages your compiler should be generating. This is telling you that you didn't provide a return type for the function main(). In C++, where you posted this C program, main() must be defined to return an int and you should return an int from this function. Since this is really a C program main should be defined to return an int and you should return an int from this function. In fact the current C standard also requires main to return an int.

Code:

int main()
{

   return 0;
}

The rest of the "error" messages are also self-explanatory if you understand how to properly use the scanf() function. I suggest you review your documentation for that standard function.

Jim

@gim in code::blocks are u using gnu/gcc compiler? how did u increased the errors and warnings as i could only increase the errors.
rest i work on linux at school and there return type mentioning is not necessory .thats y i never came across mentioning a return type .
plus what does this mean : main.c|69|warning: control reaches end of non-void function [-Wreturn-type]|

guys i removed [code]scanf("%d",trys->data);[/code] with

Code:

scanf("%d",&num);

    trys->data=num;

still program is crashing