C code to implement Link list with all operations

This program will show how to:

1. Append element at the end of link list
2. Concatenate two link lists
3. Free all nodes in a link list
4. Reverse a link list
5. Delete last element of link list
6. Delete nth element of link list
7. Combine two ordered link list into single ordered link list
8. Find union of two link lists
9. Find intersection of two link lists
10. Insert after nth element in a link list
11. Delete every second element of a link list
12. Place elements in order in a link list
13. Calculate sum of data of a link list
14. calculate number of elements in a link list
15. Make second copy of a link list
16. Move node forward to nth positions in a link list

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

typedef struct node{
int info;
struct node *link;
}NODE;
 
NODE* create(NODE *start)//for creating a list
{
 NODE *temp,*t;
 int n,i;
 printf("Enter no of nodes you want to insert:");
 scanf("%d",&n);
 for(i=0;i<n;i++)
 {
  temp=(NODE*) malloc(sizeof(NODE));
  printf("Enter data for node %d:",i+1);
  scanf("%d",&temp->info);
  temp->link=NULL;
  if(start==NULL) 
   start=temp;
  else
  {
   t=start;
   while(t->link!=NULL)
    t=t->link;
   t->link=temp;
  }
 }
 return start;
}

void disp(NODE *start)//for printing a list
{
 NODE *t;
 printf("
Elements of the list:");
 for(t=start;t!=NULL;t=t->link)
 {
  if(t->link!=NULL)
   printf("%d->",t->info);
  else
   printf("%d",t->info);
 }
 printf("
");
}

NODE* append(NODE *start)//append element at end
{
 NODE *t,*temp;
 temp=(NODE*) malloc(sizeof(NODE));
 printf("Enter data to be appended:");
 scanf("%d",&temp->info);
 for(t=start;t->link!=NULL;t=t->link);
 t->link=temp;
 temp->link=NULL;
 return start;
}

NODE* concat(NODE *s1,NODE *s2)//concatenate 2 lists
{
 NODE *t;
 t=s1;
 while(t->link!=NULL)
  t=t->link;
 t->link=s2;
 return s1;
}
 
NODE* fr(NODE *start)//free all nodes in a list
{
 NODE *t;
 t=start;
 while(t!=NULL)
 {
  t=start;
  start=t->link;
  free(t);
 }
 return start;
} 

NODE* rev(NODE *start)//to reverse a list
{ 
 NODE *t1,*t2,*s;
 for(t1=start;t1->link!=NULL;t1=t1->link);
 s=t1;
 while(t1!=start)
 { 
  for(t2=start;t2->link!=t1;t2=t2->link);
  t1->link=t2;
  t1=t2;
 }
 t1->link=NULL;
 return s;
}

NODE* dellast(NODE *start)//delete last element
{
 NODE *t,*t2;
 for(t=start;t->link->link!=NULL;t=t->link);
 t2=t->link;
 free(t2);
 t->link=NULL;
 return start;
}

NODE* deln(NODE *start)//delete nth element
{
 int i=1,n;
 NODE *t,*t2;
 printf("
Enter pos no of element to be deleted:");
 scanf("%d",&n);
 t=start;
 if(n!=1)
 {
  while(i<n-1)
  {
   t=t->link;
   i++;
  }
  t2=t->link;
  t->link=t2->link;
  free(t2);
 }
 else
 {
  start=t->link;
  free(t);
 }
 return start;
}
NODE* sort(NODE*);
//to combine 2 ordered lists into a single ordered list
NODE* comb(NODE *s1,NODE *s2)
{
 s1=concat(s1,s2);
 s1=sort(s1);
 return s1;
}
 
NODE* uni(NODE *s1,NODE *s2)//to find the union of 2 lists
{
 NODE *s3,*t,*t2,*t3,*temp;
 int flag=1;
 s3=(NODE*) malloc(sizeof(NODE));
 s3=NULL;
 t=s1;
 while(t!=NULL)
 {
  temp=(NODE*) malloc(sizeof(NODE));
  temp->info=t->info;
  temp->link=NULL;
  if(s3==NULL)
   s3=temp;
  else
  {
   t2=s3;
   while(t2->link!=NULL)
    t2=t2->link;
   t2->link=temp;
  }
  t=t->link;
 }
 
 t2=s2;
 while(t2!=NULL)
 {
  t=s1;
  flag=1;
  while(t!=NULL)
  {
   if(t->info==t2->info)
   {
    flag=0;
    break;
   }
   t=t->link;
  }
  if(flag==1)
  {
   for(t3=s3;t3->link!=NULL;t3=t3->link);
   temp=(NODE*) malloc(sizeof(NODE));
   temp->info=t2->info;
   t3->link=temp;
   temp->link=NULL;
  }   
  t2=t2->link;
 }
 return s3;
}

NODE* inter(NODE *s1,NODE *s2)//to find the intersection of 2 lists
{
 NODE *s3,*t1,*t2,*t3,*temp;
 s3=(NODE*) malloc(sizeof(NODE));
 s3=NULL;
 t1=s1;
 while(t1!=NULL)
 {
  t2=s2;
  while(t2!=NULL)
  {
   if(t1->info==t2->info)
   {
    temp=(NODE*) malloc(sizeof(NODE));
    temp->info=t1->info;
    temp->link=NULL;
    if(s3==NULL)
     s3=temp;
    else
    {
     for(t3=s3;t3->link!=NULL;t3=t3->link);
     t3->link=temp;
    }
    break;
   }
   t2=t2->link;
  }
  t1=t1->link;
 }  
 return s3;
} 

NODE* insertn(NODE *s)//to insert at nth position
{
 NODE *t,*t2,*temp;
 int n,i=1;
 printf("Enter data:");
 temp=(NODE*) malloc(sizeof(NODE));
 scanf("%d",&temp->info);
 printf("Enter position no at which element has to be inserted:");
 scanf("%d",&n);
 t=s;
 if(n!=1)
 {
  while(i<n-1)
  {
   t=t->link;
   i++;
  }
  t2=t->link;
  t->link=temp;
  temp->link=t2;
 }
 else
 {
  temp->link=s;
  s=temp;
 }
 return s;
}
  
NODE* del2(NODE *s)//delete every 2nd element in a list
{
 NODE *t1,*t2;
 t1=s;
 while(t1!=NULL)
 {
  t2=t1->link;
  t1->link=t2->link;
  free(t2);
  t1=t1->link;
 }
 return s;
} 

NODE* sort(NODE *s)//to place elements in increasing order
{
 NODE *t1,*t2;
 int temp;
 for(t1=s;t1->link!=NULL;t1=t1->link)
 {
  for(t2=t1->link;t2!=NULL;t2=t2->link)
  {
   if(t1->info>t2->info)
   {
    temp=t1->info;
    t1->info=t2->info;
    t2->info=temp;
   }
  }
 }
 return s;
}

int sum(NODE *s)//to find the sum of elements in a list
{
 int sum=0;
 NODE *t;
 for(t=s;t!=NULL;t=t->link)
  sum+=t->info;
 return sum;
}

int elements(NODE *s)//to find the number of elements in a list
{
 int n=0;
 NODE *t;
 for(t=s;t!=NULL;t=t->link)
  n++;
 return n;
}

NODE* copy(NODE *s1)//to make a second copy of the list
{
 NODE *s2,*t,*temp,*t2;
 s2=NULL;
 t=s1;
 while(t!=NULL)
 {
  temp=(NODE*) malloc(sizeof(NODE));
  temp->info=t->info;
  temp->link=NULL;
  if(s2==NULL)
   s2=temp;
  else
  {
   t2=s2;
   while(t2->link!=NULL)
    t2=t2->link;
   t2->link=temp;
  }
  t=t->link;
 }
 return s2;
} 
   
NODE* forward(NODE *s)//to forward a node by n positions
{
 NODE *t1,*t2,*t3;
 int n1,n2,i;
 printf("Enter position of the node you want to move:");
 scanf("%d",&n1);
 printf("Enter no of positions you want to move:");
 scanf("%d",&n2);
  t1=s;
  i=1;
  while(i<n1)
  {
   t1=t1->link;
   i++;
  }
  t2=s;
  i=1;
  while(i<n1+n2)
  {
   t2=t2->link;
   i++;
  }
  t3=s;
  if(t1!=s)
  while(t3->link!=t1)
   t3=t3->link;
  t3->link=t1->link;
  if(t1==s)
   s=s->link;
  t1->link=t2->link;
  t2->link=t1; 
 return s;
} 

  
void main()
{
 NODE *s1,*s2;
 int ch;
 s1=NULL;
 s2=NULL;
 while(1)
 {
  clrscr();
  printf("Enter choice:
");
  printf(" 1.Append element at end
2.Concatinate two lists
");
  printf(" 3.Free all nodes in a list
4.Reverse a list
");
  printf(" 5.Delete last element
6.Delete nth element
");
  printf(" 7.Combine two ordered list into single ordered list
");
  printf(" 8.Find union of two lists
9.Find intersection of two lists
");
  printf("10.Insert after nth element
11.Delete every second element
");
  printf("12.Place elements in order
13.Return sum of data
");
  printf("14.Return number of elements
15.Make second copy of list
");
  printf("16.Move node forward to n positions
17.Exit
");
  scanf("%d",&ch);
  clrscr();
  if(ch>0&&ch<=16)
   s1=create(s1);
   disp(s1);
  switch(ch)
  {
   case 1:s1=append(s1);break;
   case 2:s2=create(s2);disp(s2);s1=concat(s1,s2);break;

   case 3:s1=fr(s1);
   printf("List freed
");
   disp(s1);
   break;
   
   case 4:s1=rev(s1);break;
   case 5:s1=dellast(s1);break;
   case 6:s1=deln(s1);break;
   case 7:s2=create(s2);disp(s2);s1=comb(s1,s2);break;
   case 8:s2=create(s2);disp(s2);s1=uni(s1,s2);break;
   case 9:s2=create(s2);disp(s2);s1=inter(s1,s2);break;
   case 10:s1=insertn(s1);break;
   case 11:s1=del2(s1);break;
   case 12:s1=sort(s1);break;
   case 13:printf("Sum of elements=%d",sum(s1));break;
   case 14:printf("Number of elements=%d",elements(s1));break;
   
   case 15:
   s2=copy(s1);
   printf("Second list:
");
   disp(s2);
   break;
   
   case 16:s1=forward(s1);break;
   case 17:exit(0);break;
   default:printf("Wrong choice.Enter again");break;
  }
  if(ch!=3&&ch!=13&&ch!=14&&ch!=15&&ch>0&&ch<=16)
  {
   printf("
Result:");
   disp(s1);
  }
   s1=fr(s1);
   s2=fr(s2);
   getch();
 }   
}

Related Posts by Categories