Singly Linked List: Concatenate two lists

Singly Linked List: Concatenate two lists

#include<stdio.h>

#include<malloc.h>

#include<stdlib.h>

struct node

{

                int data;

                struct node *link;

};

typedef struct node * NODE;

NODE getnode()

{

                NODE x;

                x = (NODE)malloc(sizeof(struct node));

                if(x==NULL)

                {

                                printf("\nInsufficient memory");

                                exit(0);

                }

                x->link = NULL;

                return x;

}

NODE insert(NODE first)

{

                int val;

                NODE temp, cur;

                temp = getnode();

                printf("\nEnter the value: ");

                scanf("%d", &val);

                temp->data = val;

                if(first==NULL)

                                return temp;

                cur = first;

                while(cur->link!=NULL)

                {

                                cur = cur->link;

                }

                cur->link = temp;

                return first;

}

NODE concat(NODE first, NODE second)

{

                NODE cur;

                if(first==NULL)

                                return second;

                if(second==NULL)

                                return first;

                cur =first;

                while(cur->link!=NULL)

                {

                                cur = cur->link;

                }

                cur->link = second;

                return first;

}

void display(NODE first)

{

                NODE cur;

                cur = first;

                printf("\nContents are:\n");

                if(cur == NULL)

                                printf("\nList is empty. Nothing to display.");

                else

                {

                                while(cur!=NULL)

                                {

                                                printf("| %d | %d | => ", cur->data, cur->link);

                                                cur = cur->link;

                                }

                }

}

void main()

{

                int ch, i , n1,n2;

                NODE first = NULL;

                NODE second =NULL;

                printf("\nEnter number of nodes for list1: ");

                scanf("%d", &n1);

                for(i=0;i<n1;i++)

                                first = insert(first);

                printf("\nEnter number of nodes for list2: ");

                scanf("%d", &n2);

                for(i=0;i<n2;i++)

                                second = insert(second);

                first = concat(first, second);

                display(first);

}

Output:

Enter number of nodes for list1: 4

Enter the value: 11

Enter the value: 12

Enter the value: 13

Enter the value: 14

Contents are:

| 11 | 4986632 | => | 12 | 4994040 | => | 13 | 4994056 | => | 14 | 0 |

Enter number of nodes for list2: 3

Enter the value: 15

Enter the value: 16

Enter the value: 17

Contents are:

| 15 | 4994088 | => | 16 | 4994104 | => | 17 | 0 |

After concatenation:

Contents are:

| 11 | 4986632 | => | 12 | 4994040 | => | 13 | 4994056 | => | 14 | 4994072 | => | 15 | 4994088 | =>  | 16 | 4994104 | => | 17 | 0 |