LinkedListTest.c

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

struct node {
    int data;
    struct node *next;
}; //*first = NULL;
struct node *list = NULL;
// void createLinkedList(int A[], int n) {
//     struct node *t, *last;
//     first = (struct node *)malloc(sizeof(struct node));
//     first->data = A[0];
//     first->next = NULL;
//     last = first;
    
//     for (int i = 1; i < n; i++) {
//         t = (struct node *)malloc(sizeof(struct node));
//         t->data = A[i];
//         t->next = NULL;
//         last->next = t;
//         last = t;
//     }
// }

// void DisplayNode (struct node *node, int n) {
//     while (node != NULL) {
//         printf("%d", node->data);
//         node = node->next;
//     }
// }

void createLinkedList(int data) {
    struct node *temp, *n;
    //head = (struct node *)malloc(sizeof(struct node));
    //head->data = data;
    //head->next = NULL;
    //n = list;
    if (list == NULL) {
        printf("Entering 1st node \n");
        list = (struct node *)malloc(sizeof(struct node));
        printf("%p", list);
        list->data = data;
        printf("%d", list->data);
        list->next = NULL;
        printf("%p", list->next);
        //n = list;
    }
    else {
        n = list;
        while (n->next != NULL) {
            n = n->next;
        }
        temp = (struct node *)malloc(sizeof(struct node));
        temp->data = data;
        temp->next = NULL;
        n->next = temp;
        //n = temp;
        //t = temp;
        //head->next = temp;
    }
}

void DisplayLinkedList(struct node *node) {
    while (node != NULL) {
        printf("%d ", node -> data);
        node = node -> next;
    }
    printf("\n");
}

int countNodes(struct node *node) {
    int count = 0;
    while (node != NULL) {
        count = count + 1;
        node = node->next;
    }
    printf("No of nodes are %d \n", count);
    return count;
}

int sumeOfNodes(struct node *node) {
    int sum = 0;
    while (node != NULL) {
        int next = 
        sum = sum + node -> data;
        node = node -> next;
    }
    return sum;
}

int maxNode(struct node *node) {
    int max = node -> data;
    while (node != NULL) {
        if (node -> data > max) {
            max = node -> data;
        }
        node = node -> next;
    }
    return max;
}

int searchLinkedList(struct node *node, int target) {
    while (node != NULL) {
        if (node -> data == target) {
            printf("found at address %p \n", node);
            return 0;
        }
        node = node -> next;
    }
    printf("Not found\n");
    
}

void prepend(int data) {
    struct node *n;
    if (list == NULL) {
        printf("Node is Empty \n");
        list = (struct node *) malloc (sizeof(struct node));
        list -> data = data;
        list -> next = NULL;
    }
    else {
        n = (struct node *) malloc (sizeof(struct node));
        n -> data = data;
        n -> next = list;
        list = n;
    }
    
}

// void insertAtPosition(struct node *node, int data, int pos) {
//     struct node *n, *temp;
//     int count = 0;
//     while (node != NULL) {
//         count = count + 1;
//         if (pos == count + 1) {
//             break;
//         }
//         node = node -> next;
//     }
//     temp = node -> next;
//     n = (struct node *) malloc (sizeof(struct node));
//     n -> data = data;
//     n -> next = temp;
//     node -> next = n;
    
// }


void insertAtPosition(struct node *node, int data, int pos) {
    struct node *n, *temp;
    if (pos == 0 /*|| pos == 1*/) {
        printf("Inserting at position 0\n");
        //prepend(data);
        if (list == NULL) {
            printf("LinkedList is empty so creating 1st one\n");
            list = (struct node *) malloc (sizeof(struct node));
            list->data = data;
            list->next = NULL;
            //node = n;
        }
        else {
            n = (struct node *) malloc (sizeof(struct node));
            n->data = data;
            n->next= list;
            list = n;

        }
        
    }
    else {
        int count = 0;
        while (node != NULL) {
            //count = count + 1;
            if (pos == count + 1) {
                break;
            }
            node = node -> next;
            count = count + 1;
        }
        temp = node -> next;
        n = (struct node *) malloc (sizeof(struct node));
        n -> data = data;
        n -> next = temp;
        node -> next = n;
    }
    
}
/* 
This does not delete node at 0
void deleteNode(int pos) {
    struct node *node, *temp;
    if (list == NULL) {
        printf("Linked List is empty \n");
    }
    else {
        node = list;
        for (int i = 0; i < pos - 1; i++) {
            node = node->next;
        }
        temp = node -> next -> next;
        printf("deleting node at pos %d that has data : %d\n", pos, node->next->data);
        free(node->next);
        node->next = temp;
    }
}
*/

void deleteNode(int pos) {
    struct node *node, *temp;
    if (list == NULL) {
        printf("Linked List is empty \n");
    }
    else if (pos == 0) {
        
        node = list;
        printf("deleting node at pos %d that has data : %d\n", pos, node->data);
        temp = node -> next;
        free(node);
        list = temp;
    }
    else {
        node = list;
        for (int i = 0; i < pos - 1; i++) {
            node = node->next;
        }
        temp = node -> next -> next;
        printf("deleting node at pos %d that has data : %d\n", pos, node->next->data);
        free(node->next);
        node->next = temp;
    }
}

int main() {
    insertAtPosition(list, 3, 0);
    createLinkedList(5);  createLinkedList(10); createLinkedList(15);
    prepend(11);
    DisplayLinkedList(list);
    
    int count = countNodes(list);
    printf("Countes = %d\n", count);
    
    int sum = sumeOfNodes(list);
    printf("Sum = %d\n", sum);

    createLinkedList(12);
    createLinkedList(18);
    createLinkedList(2);
    createLinkedList(10);

    prepend(9);
    prepend(0);
    
    
    int max = maxNode(list);
    printf("Maximum in Node is %d\n", max);
    
    DisplayLinkedList(list);

    searchLinkedList(list, 11);
    insertAtPosition(list, 13, 1);
    printf("List after inserting at location 1\n");
    DisplayLinkedList(list);
    insertAtPosition(list, 13, 2);
    printf("List after inserting at location 2\n");
    DisplayLinkedList(list);

    insertAtPosition(list, 7, 4);
    insertAtPosition(list, 7, 9);

    insertAtPosition(list, 1, 0);
    insertAtPosition(list, 4, 0);
    insertAtPosition(list, 1, 1);
    
    DisplayLinkedList(list);

    deleteNode(3);
    printf("After Deleting node\n");
    DisplayLinkedList(list);

    deleteNode(0);
    printf("After Deleting node\n");
    DisplayLinkedList(list);

    deleteNode(1);
    printf("After Deleting node\n");
    DisplayLinkedList(list);

    deleteNode(2);
    printf("After Deleting node\n");
    DisplayLinkedList(list);
}