Merge pull request #1755 from punitcrypto2002/master

Linked List Program in C

16.LiLi4.c

@@ -0,0 +1,241 @@
+/*Linked List creation and working with double pointers.
+Case 1 for creating
+Case 2 for displaying
+Case 3 for adding node in beginning
+Case 4 for adding node before a given value
+Case 5 for deleting a node of a given position
+Case 6 for deleting a node with even value
+Case 7 for counting no. of nodes
+*/
+
+#include<stdio.h>
+#include<stdlib.h>             //for dynamic memory allocation
+struct node
+{
+    int data;
+    struct node *link;
+};
+void createlist(struct node **h, int N)
+{
+    int val,i;
+    struct node *ptr=NULL;
+    struct node *temp=NULL;
+    for(i=0;i<N;i++)
+    {
+        printf("Enter the value to be inserted in node %d:\n",i+1);
+        scanf("%d",&val);
+        temp= (struct node*)malloc(sizeof(struct node));
+        temp->data=val;
+        temp->link=NULL;
+        if(*h==NULL)
+        {
+            *h=temp;
+            ptr=temp;
+        }
+        else
+        {
+            ptr->link=temp;
+            ptr=temp;
+        }
+    }
+    printf("Linked list created!!\n\n");
+}
+void displaylist(struct node **h)
+{
+    struct node* ptr;
+    ptr=*h;
+    printf("The linked list is:\n");
+    while(ptr!=NULL)
+    {
+        printf("%d ",ptr->data);
+        ptr=ptr->link;
+    }
+    printf("\n\n");
+}
+void addnodebeg(struct node**h)
+{
+    int val;
+    struct node* temp=(struct node*)malloc(sizeof(struct node));
+    printf("Enter the value to be inserted:\n");
+    scanf("%d",&val);
+    temp->data=val;
+    temp->link=*h;
+    *h=temp;
+    printf("A node is added in the beginning of the linked list !!\n\n");
+}
+void addnodeval(struct node**h,int x)
+{
+    int val,item,p,i;
+    struct node*ptr=*h;
+    printf("Enter the value from linked list before which another node is to be added: ");
+    scanf("%d",&item);
+    printf("Value of x is:%d\n",x);
+    for(i=0;i<x;i++)
+    {
+        if(ptr->data==item)
+        {
+            p=i+1;
+        }
+            ptr=ptr->link;
+
+    }
+    printf("The position of the value,%d in the linked list is %d\n",item,p);
+    printf("Enter the value to be inserted: \n ");
+    scanf("%d",&val);
+    struct node* temp=(struct node*)malloc(sizeof(struct node));
+    temp->data=val;
+    ptr=*h;
+    if(p==1)
+    {
+        temp->link=*h;
+        *h=temp;
+    }
+    else
+    {
+        for(i=1;i<p-1;i++)
+        {
+            ptr=ptr->link;
+        }
+        temp->link=ptr->link;
+        ptr->link=temp;
+
+    }
+
+    printf("A node is added before the value %d!!\n\n",item);
+}
+void delnode(struct node**h,int x)
+{
+    struct node* curr=*h;
+    struct node* prev=*h;
+    struct node* q;
+    int dn,p,i;
+    printf("Enter the position of the node which is to be deleted: \n");
+    scanf("%d",&p);
+    if(p<=x && p>=1)
+    {
+        for(i=1;i<=p;i++)
+        {
+            if(i==p)
+            {
+                if(p==1)
+                {
+                    q=curr;
+
+                    dn=curr->data;
+                    curr=curr->link;
+                    *h=curr;
+                    free(q);
+                    printf("The node of position 1 is deleted which had value %d !\n\n",dn);
+                }
+                else
+                {
+                    q=curr;
+                    dn=curr->data;
+                    prev->link=curr->link;
+                    curr=curr->link;
+                    free(q);
+                    printf("The node of position %d is deleted which had value %d !\n\n",p,dn);
+
+                }
+
+            }
+            prev=curr;
+            curr=curr->link;
+        }
+    }
+    else
+    {
+        printf("this position does not exist in the Linked list!!\n\n");
+    }
+}
+void delnodeeven(struct node**h)
+{
+    struct node* curr=*h;
+    struct node* prev=*h;
+    struct node* q;
+    int p=1;
+
+    while(curr!=NULL)
+    {
+        if(curr->data%2==0)
+        {
+            if(p==1)
+            {
+                q=curr;
+                *h=curr->link;
+                curr=curr->link->link;
+                free(q);
+            }
+            else
+            {
+                q=curr;
+                prev->link=curr->link;
+                curr=curr->link;
+                free(q);
+            }
+        }
+        else
+        {
+            prev=curr;
+            curr=curr->link;
+        }
+        p++;
+    }
+    printf("the desired nodes were deleted!!\n\n");  
+}
+int countnode(struct node**h )
+{
+    int cn=0;
+    struct node*ptr=*h;
+    while(ptr!=NULL)
+    {
+        ptr=ptr->link;
+        cn++;
+    }
+    printf("The no. of nodes are:%d\n\n\n",cn);
+    return cn;
+}
+int main()
+{
+    struct node* head=NULL;
+    int c,n,ch;
+    printf("Enter the no. of nodes: ");
+    scanf("%d",&n);
+    for(;;)
+    {
+    printf("Enter 1 to create list\nEnter 2 to display list\nEnter 3 to add a node in the beginning\nEnter 4 to add node before a specific value of the linked list\nEnter 5 to delete a node\n");
+    printf("Enter 6 to delete the nodes with an even value\nEnter 7 to count the no. of nodes in Linked List\n");
+    printf("Enter your choice: ");
+    scanf("%d",&ch);
+    switch(ch)
+    {
+        case 1:
+                createlist(&head,n); 
+                break;
+        case 2:
+                displaylist(&head);
+                break;
+        case 3:
+                addnodebeg(&head);
+                break;
+        case 4:
+                c=countnode(&head);
+                addnodeval(&head,c);
+                break;
+        case 5:
+                c=countnode(&head);
+                delnode(&head,c);
+                break;
+        case 6:
+                delnodeeven(&head);
+                break;
+        case 7:
+                countnode(&head);
+                break;
+        default:
+                printf("wrong choice!");
+    }
+
+    }
+    return 0;
+}