Problem in Adjancey list

**vaibhav** · 11-18-2005

I have made program for an adjancy list. First column is dynamically allocated and it's next nodes are allocated through linked list. I am not getting proper output.Pls help

Code:

#include<stdio.h>
#include<conio.h>
#include<malloc.h>

struct node
{
int info;
struct node *next;
}*temp;

struct fcol
{
int info;
struct node *next;
}*firstcol;
void createlist(int*,int);

int main()
{
int *a,num,i,j;
clrscr();
printf("Enter the number of nodes...");
scanf("%d",&num);

a=(int *)malloc(num*num*sizeof(int));

printf("Enter the adjacency matrix....");
for(i=0;i<=num-1;i++)
{
  for(j=0;j<=num-1;j++)
      scanf("%d",&a[i*num+j]);
}

createlist(a,num);
for(i=0;i<=num-1;i++)
{
  printf("node%d",firstcol[i].info);
  for(temp=firstcol[i].next;temp!=NULL;temp=temp->next)
     printf("->node%d",temp->info);
  printf("\n");
}
getch();
return(0);
}


void createlist(int a[],int num)
{
int *row,i,j;
temp=NULL;
firstcol=NULL;
//allocates 1d array for first col
firstcol=(struct fcol*)malloc(num*sizeof(struct fcol));

for(i=0;i<=num-1;i++)
{
  firstcol[i].info=i+1;
  firstcol[i].next=NULL;
}

for(i=0;i<=num-1;i++)
{
  for(j=0;j<=num-1;j++)
  {
    if(a[i*num+j]==1)
    {
       temp=firstcol[i].next;
       while(temp->next!=NULL)
	 temp=temp->next;

       temp->next=(struct node*)malloc(sizeof(struct node));
       temp=temp->next;
       temp->info=j+1;
       printf("\t%d",temp->info);
       temp->next=NULL;
    }
  }
}
}

**nvoigt** · 11-18-2005

I am not getting proper output.Pls help

My advice would be to change your program, so it gives "proper" output.

You could also ask a smart question ( see sig ).

**cbastard** · 11-18-2005

Code:

  firstcol[i].next=NULL;
  temp=firstcol[i].next;
 while(temp->next!=NULL)
temp->next=(struct node*)malloc(sizeof(struct node));

Now can you see some thing.

some others.

Code:

a=(int *)malloc(num*num*sizeof(int));

Casting malloc.read faq.

Code:

void createlist(int*,int);

remember array are not pointers although this is not giving error

**dwks** · 11-19-2005

Code:

#include <malloc.h>

Most compilers don't need that header -- if yours does, get a new compiler.

Code:

void createlist(int*,int);

void createlist(int a[],int num)

As cbastard said, your function prototype and definitions are different.

Why do you have a struct fcol?

Code:

struct node
{
int info;
struct node *next;
}*temp;

struct fcol
{
int info;
struct node *next;
}*firstcol;

->

Code:

struct node
{
int info;
struct node *next;
} *firstcol, *temp;

Unless you're planning to make them different.

And you're casting malloc. And you're not freeing your malloc()ed data.

I am not getting proper output.

What output are you getting, then? And what is "proper" output?

**quzah** · 11-19-2005

Originally Posted by dwks

Code:

void createlist(int*,int);

void createlist(int a[],int num)

As cbastard said, your function prototype and definitions are different.

Actually, it's not really true. Arrays degrade into a pointer to their first element when passed. Any time you pass a single dimension array, it degrades to a pointer of that type. Thus, passing an "int[]", ends up a "int*". So it really doesn't matter in this case. After all, this is perfectly legal:

Code:

int array[] = { 1, 2, 3 };
int *ptr = array;

ptr[0] = 5; /* <--- Perfectly fine to do. */

Quzah.

**dwks** · 11-19-2005

Okay, thanks. I always knew they had the same result, but I didn't know they were compatible.

Well, at least you can't say that vaibhav is freeing his memory.

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