Single-Linked Lists

How do you create a single linked list that creates a node and inserts it into an already existing list and sorts the list in order (if you have a list of integers), and prints the new list?

Thanks,
Husslela

 

hai, i have attached linked list program in 'c' along this post.... if u compile it will show 2 warning message, just ignore it and execute the program....
take care...

Code:

#include<conio.h>
#include<stdio.h>
void creation(int);
void display();
void insertion(int,int);
void deletion(int);

struct list
{
  int num;
  struct list *next;
}*head, *l;

void main()
{
  int n1,ch,pos,val;
  clrscr();
  printf("enter the no of nodes to be entered : ");
  scanf("%d",&n1);

  do
  {
     clrscr();
     printf("\n1.creation\n2.insertion\n3.deletion\n4.display\n5.exit\n");
     printf("\nenter ur choice : ");
     scanf("%d",&ch);
     switch(ch)
     {
	case 1:
		creation(n1);
		break;
	case 2:
		printf("\n\nenter the postion in which to be inserted : ");
		scanf("%d",&pos);
		printf("\n\nenter the value : ");
		scanf("%d",&val);
		insertion(pos,val);
		break;
	case 3:
		printf("\n\nenter the position to be deleted : ");
		scanf("%d",&pos);
		deletion(pos);
		break;
	case 4:
		display();
		getch();
		break;
	case 5:
		exit(0);
     }
  }while(ch!=5);

  getch();
}

/*  CREATION   */
/*  --------   */


void creation(int n1)
{
  int i,n;
  head=((struct list *)malloc(sizeof(struct list)));
  l=head;
  for(i=0;i<n1;i++)
  {
     printf("enter the %d node : ",i+1);
     scanf("%d",&n);
     l->num=n;
     l->next=((struct list *)malloc(sizeof(struct list)));
     l=l->next;
  }
  l->next=0;

}

/*  DISPLAY   */
/*  -------   */


void display()
{
  l=head;
  printf("\nthe nodes entered are : ");

  while(l->next>0)
  {
    printf("%d\t",l->num);
    l=l->next;
  }
  printf("null");
}


/*  INSERTION   */
/*  ---------   */

void insertion(pos,val)
{
  int i;
  struct list *x,*y;
  l=head;
  i=2;
  if(pos==1)
  {
    x=((struct list *)malloc(sizeof(struct list)));
    x->num=val;
    x->next=l;
    head=x;
  }
  else
  {
	while(l->next>0)
	{
	    if(pos==i-1)
	    {
	      x=((struct list *)malloc(sizeof(struct list)));
	      x->num=val;
	      x->next=l;
	      y->next=x;
	    }
	    y=l;
	    l=l->next;
	    i++;
	}
  }
}

/*  DELETION   */
/*  --------   */


void deletion(pos)
{
  int i;
  struct list *y;
  l=head;
  i=1;
  if(pos==1)
  {   head=l->next;  }
  else
  {
    while(l->next>0)
    {
      if(pos==i)
      { l=l->next;
	y->next=l;
	break;
      }
      y=l;
      l=l->next;
      i++;
    }
  }
}

 

Regarding the C code, just what warnings would you advise a user to ignore? Most warnings are indicative of an error on the part of the coder, even it it happens, from time to time, to not be fatal. Would you be referring to warnings regarding your use of 'malloc', because you forgot to #include stdlib.h or malloc.h?

Further, you have a serious error that the compiler won't flag. You don't test the return from malloc to see if it's NULL. The system is perfectly within its rights to refuse to allocate the memory and return a NULL indicating that. Trying to dereference that NULL will send your program off into the weeds to barf on its shoes.

Given all that, and the use of non-portable things like conio.h (whose functions actually add virtually nothing to your program), this is not a robust example of a linked-list implementation.

 

Good links, and if the OP is going to use assembly language, the overall procedures are the same.

 

hello DaWei,
thanx for ur valueable note.... it been a practise for me to include both header files in every program.... and thanx again for ur note.... i have planned to do a project, in that i need to get a part of input from an electronic counter..... i have an intermediate knowledge in c and vb. can u suggest me which would be preferable for this...

 

You should start a separate thread for a different question. Getting input from an external device will depend entirely upon your system implementation and its operating system. Access to various ports is not as readily available from desktop systems as it once was (that's a protective benefit). However, each system will probably provide some methods for serial and parallel port I/O. Again, they will vary depending upon what you have.