Concatenate Two Single Linked Lists

/*
Write a program  to concatenate two single linked lists.
*/

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

struct node
{
    int info;
    struct node *link;
};

struct node *create_list(struct node *);
struct node *concat( struct node *start1,struct node *start2);
struct node *addatbeg(struct node *start, int data);
struct node *addatend(struct node *start,int data);
void display(struct node *start);

main()
{
    struct node *start1=NULL,*start2=NULL;
    start1=create_list(start1);
    start2=create_list(start2);
    printf("First list is  : ");
    display(start1);
    printf("Second list is  : ");
    display(start2);
    start1=concat(start1, start2);
    printf("Concatenated list is  : ");
    display(start1);
}

struct node *concat( struct node *start1,struct node *start2)
{
    struct node *ptr;
    if(start1==NULL)
    {
        start1=start2;
        return start1;
    }
    if(start2==NULL)  
        return start1;
    ptr=start1;
    while(ptr->link!=NULL)
        ptr=ptr->link;
    ptr->link=start2;   
    return start1;
}

struct node *create_list(struct node *start)
{
    int i,n,data;
    printf("Enter the number of nodes : ");
    scanf("%d",&n);
    start=NULL;
    if(n==0)
        return start;

    printf("Enter the element to be inserted : ");
    scanf("%d",&data);
    start=addatbeg(start,data);

    for(i=2;i<=n;i++)
    {
        printf("Enter the element to be inserted : ");
        scanf("%d",&data);
        start=addatend(start,data);   
    }
    return start;
}

void display(struct node *start)
{
    struct node *p;
    if(start==NULL)
    {
        printf("List is empty\n");
        return;
    }
    p=start;
    while(p!=NULL)
    {
        printf("%d ", p->info);
        p=p->link;
    }
    printf("\n");
}

struct node *addatbeg(struct node *start,int data)
{
    struct node *tmp;
    tmp=(struct node *)malloc(sizeof(struct node));
    tmp->info=data;
    tmp->link=start;
    start=tmp;
    return start;
}

struct node *addatend(struct node *start, int data)
{
    struct node *p,*tmp;
    tmp= (struct node *)malloc(sizeof(struct node));
    tmp->info=data;
    p=start;
    while(p->link!=NULL)
        p=p->link;
    p->link=tmp;
    tmp->link=NULL;
    return start;
}




Related Posts,

 1. Single Linked List
 2. Single Linked List with Header Node 
 3. Sorting a Single Linked List

 

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