Thursday, 22 September 2016

Singly Linked List: Insert at End

Singly Linked List: Insert at End


#include<stdio.h>
#include<stdlib.h>
struct node
{
            int data;
            struct node *link;
};
typedef struct node * NODE;

NODE getnode();
NODE insert_at_end(NODE first, int item);
void display( NODE first);

NODE getnode()
{
            NODE x;
            x = (NODE)malloc(sizeof(struct node));
            x->link = NULL;
            return x;
}
void display(NODE first)
{
            NODE cur;
            cur = first;
            printf("\nContents are:");
            if(cur == NULL)
                        printf("\nList is empty. Nothing to display.");
            else
            {
                        while(cur!=NULL)
                        {
                                    printf("%d  ", cur->data);
                                    cur = cur->link;
                        }
            }
}

NODE insert_at_end(NODE first, int item)
{
            NODE temp, cur;
            temp = getnode();
            temp->data = item;

            /*Case 1: List is empty*/        
            if(first == NULL)
                        return temp;
            /*Case 2: List has nodes: Traverse till the end of the list*/
            cur = first;
            while(cur->link != NULL)
            {
                        cur = cur->link;
            }
            /*Set the link field of last node to point to temp node*/
            cur->link = temp;
            return first;
}

void main()
{
            int ch, item;
            NODE first = NULL;
            while(1)
            {
                        printf("\n\n~~MENU~~");
                        printf("\n1.Insert at end");
                        printf("\n2.Display");
                        printf("\n3.exit");
                        printf("\nEnter your choice: ");
                        scanf("%d",&ch);
                        switch(ch)
                        {
                                    case 1:             printf("\nEnter the value: ");
                                                            scanf("%d", &item);
                                                            first = insert_at_end(first, item);
                                                            break;
                                    case 2:             display(first);
                                                            break;
                                    case 3:     exit(0);
                    }
            }
}

Output:
~~MENU~~
1.Insert at end
2.Display
3.exit
Enter your choice: 1
Enter the value: 11

~~MENU~~
1.Insert at end
2.Display
3.exit
Enter your choice: 1
Enter the value: 12

~~MENU~~
1.Insert at end
2.Display
3.exit
Enter your choice: 2
Contents are: 11  12

~~MENU~~
1.Insert at end
2.Display
3.exit