insertion singly linked list in c

1/**
2 * C program to insert a new node at the beginning of a Singly Linked List
3 */
4
5#include <stdio.h>
6#include <stdlib.h>
7
8
9/* Structure of a node */
10struct node {
11    int data;          // Data 
12    struct node *next; // Address 
13}*head;
14
15
16void createList(int n);
17void insertNodeAtBeginning(int data);
18void displayList();
19
20
21int main()
22{
23    int n, data;
24
25    /*
26     * Create a singly linked list of n nodes
27     */
28    printf("Enter the total number of nodes: ");
29    scanf("%d", &n);
30    createList(n);
31
32    printf("\nData in the list \n");
33    displayList();
34
35    /*
36     * Insert data at the beginning of the singly linked list
37     */
38    printf("\nEnter data to insert at beginning of the list: ");
39    scanf("%d", &data);
40    insertNodeAtBeginning(data);
41
42    printf("\nData in the list \n");
43    displayList();
44
45    return 0;
46}
47
48
49/*
50 * Create a list of n nodes
51 */
52void createList(int n)
53{
54    struct node *newNode, *temp;
55    int data, i;
56
57    head = (struct node *)malloc(sizeof(struct node));
58
59    /*
60     * If unable to allocate memory for head node
61     */
62    if(head == NULL)
63    {
64        printf("Unable to allocate memory.");
65    }
66    else
67    {
68        /*
69         * Input data of node from the user
70         */
71        printf("Enter the data of node 1: ");
72        scanf("%d", &data);
73
74        head->data = data; // Link data field with data
75        head->next = NULL; // Link address field to NULL
76
77        temp = head;
78
79        /*
80         * Create n nodes and adds to linked list
81         */
82        for(i=2; i<=n; i++)
83        {
84            newNode = (struct node *)malloc(sizeof(struct node));
85
86            /* If memory is not allocated for newNode */
87            if(newNode == NULL)
88            {
89                printf("Unable to allocate memory.");
90                break;
91            }
92            else
93            {
94                printf("Enter the data of node %d: ", i);
95                scanf("%d", &data);
96
97                newNode->data = data; // Link data field of newNode with data
98                newNode->next = NULL; // Link address field of newNode with NULL
99
100                temp->next = newNode; // Link previous node i.e. temp to the newNode
101                
102                temp = temp->next; 
103            }
104        }
105
106        printf("SINGLY LINKED LIST CREATED SUCCESSFULLY\n");
107    }
108}
109
110
111/*
112 * Create a new node and inserts at the beginning of the linked list.
113 */
114void insertNodeAtBeginning(int data)
115{
116    struct node *newNode;
117
118    newNode = (struct node*)malloc(sizeof(struct node));
119
120    if(newNode == NULL)
121    {
122        printf("Unable to allocate memory.");
123    }
124    else
125    {
126        newNode->data = data; // Link data part
127        newNode->next = head; // Link address part
128
129        head = newNode;          // Make newNode as first node
130
131        printf("DATA INSERTED SUCCESSFULLY\n");
132    }
133}
134
135
136/*
137 * Display entire list
138 */
139void displayList()
140{
141    struct node *temp;
142
143    /*
144     * If the list is empty i.e. head = NULL
145     */
146    if(head == NULL)
147    {
148        printf("List is empty.");
149    }
150    else
151    {
152        temp = head;
153        while(temp != NULL)
154        {
155            printf("Data = %d\n", temp->data); // Print data of current node
156            temp = temp->next;                 // Move to next node
157        }
158    }
159}

1#include <iostream>
2// Linked list
3struct node {
4    int data ;
5    node * link;
6};
7
8
9node * Node(int data) {
10    node * temp = new node();
11    temp->data = data;
12    temp->link = NULL;
13    return temp;
14}
15
16void append(node ** head, int data) {
17
18    if(*head == NULL) {
19        *head =  Node(data);
20    }else {
21        node * temp = * head;
22        while (temp->link != NULL) {
23            temp=temp->link;
24        }
25        temp->link = Node(data);
26
27    }
28
29}
30
31
32// insertion at begining
33
34void insertBeg(node **head , int data) {
35    if(*head == NULL) {
36        * head = Node(data);
37    }else {
38        node * temp = Node(data);
39        temp->link = *head;
40        *head = temp;
41
42    }
43
44
45}
46// insert at specific position
47
48void addafter(node * head , int loc , int data) {
49    node * temp , * r ;
50    temp = head ;
51    for( int i = 0 ; i<loc;i++ ) {
52        temp = temp->link;
53        if(temp == NULL) {
54            cout<<"there ar less elemtns" ;
55            return;
56        }
57
58    }
59    // insert new node
60    r = Node(data);
61    r->link = temp->link;
62    temp->link = r;
63
64
65}
66
67void display(node * head) {
68
69    node * temp = head;
70    while(temp!= NULL) {
71        cout<<temp->data<<" ";
72        temp = temp->link;
73    }
74}
75
76
77
78int main() {
79    node * head = NULL;
80    append(&head,5);
81    append(&head,5);
82    append(&head,5);
83    append(&head,5);
84    display(head);
85    cout<<endl;
86    insertBeg(&head,6);
87    insertBeg(&head,6);
88    insertBeg(&head,6);
89    display(head);
90addafter(head,4,7);
91cout<<endl;
92display(head);
93
94    return 0;
95}
96