LinkedListFunctionality.c

#include <stdio.h>

#include <stdlib.h>

#include <stdbool.h>

#include <string.h>
 // A linked list node
struct Node {
    char name[50];

    int age;

    char address[100];
    int yearsOfExperience;
    struct Node* next;
};


/* Given a reference (pointer to pointer) to the head of a list
and an int, inserts a new node on the front of the list. */
void push(struct Node** head_ref, int new_age, char name[50], char address[100], int yearsOfExperience) {
    /* 1. allocate Node*/
    struct Node* new_node = (struct Node* ) malloc(sizeof(struct Node));

    /* 2. put in the age */
    new_node -> age = new_age;
    new_node -> yearsOfExperience = yearsOfExperience;
    strcpy(new_node -> name, name);
    strcpy(new_node -> address, address);

    /* 3. Make next of new node as head */
    new_node -> next = ( * head_ref);

    /* 4. move the head to point to the new Node*/
    ( * head_ref) = new_node;
}

/* Given a reference (pointer to pointer) to the head
of a list and an int, appends a new node at the end */
void append(struct Node** head_ref, int new_age, char name[50], char address[100], int yearsOfExperience) {
    /* 1. allocate Node*/
    struct Node* new_node = (struct Node* ) malloc(sizeof(struct Node));

    struct Node* last = * head_ref; /* used in step 5*/

    /* 2. put in the age */
    new_node -> age = new_age;
    new_node -> yearsOfExperience = yearsOfExperience;
    strcpy(new_node -> name, name);
    strcpy(new_node -> address, address);

    /* 3. This new node is going to be the last node, so make next
    	of it as NULL*/
    new_node -> next = NULL;

    /* 4. If the Linked List is empty, then make the new node as head */
    if ( * head_ref == NULL) {
        * head_ref = new_node;
        return;
    }

    /* 5. Else traverse till the last Node*/
    while (last -> next != NULL)
        last = last -> next;

    /* 6. Change the next of last Node*/
    last -> next = new_node;
    return;
}

/* Checks whether the value x is present in linked list */
int search(struct Node* head, int x, int pos) {
    // Base case
    if (head == NULL)
        return -1;

    // If key is present in current node, return true
    if (head -> age == x)
        return pos;

    // Recur for remaining list
    return search(head -> next, x, ++pos);
}

/* Function to reverse the linked list */
void reverse(struct Node** head_ref)
{
    struct Node* first;
    struct Node* rest;

    /* empty list */
    if (*head_ref == NULL)
       return;

    first = *head_ref;
    rest  = first->next;

    if (rest == NULL)
       return;

    reverse(&rest);
    first->next->next  = first;

    first->next  = NULL;

    *head_ref = rest;
}

void printList(struct Node* node) {
    printf("\n The list is printed in the order: age, years of experience, name, address\n");
    while (node != NULL) {
        printf("[ %d %d %s %s ]->", node -> age, node -> yearsOfExperience, node -> name, node -> address);
        node = node -> next;
    }
    printf("\n");
}

/* Driver program to test above functions*/
int sampleLinkedList(){
    struct Node* head = NULL;

    append( &head, 6, "Name1", "Address1", 10);


    push( &head, 2, "Name2", "Address2", 11);


    push( &head, 3, "Name3", "Address3", 9);


    append( &head, 10, "Name4", "Address4", 2);

    printf("\nSearched age = 10");

    int value = search(head, 10, 0);
    printf("\nPresent at position: %d", value);

    printf("\n Created Linked list is: ");
    printList(head);

    printf("\nThe reversed list is:");
    reverse(&head);
    printList(head);
    printf("\n");
}

int input(int* age, int* yearsOfExperience, char name[], char address[]){
    printf("Enter the following fields respectively: 1) Name, 2) Address, 3) Age, 4) Years of Experience:\n");
    scanf("%s%s%d%d", name, address, age, yearsOfExperience);
}

int main() {
    /* Start with the empty list */
    struct Node* head = NULL;
    int choice = 0;
    int age = 0, yearsOfExperience = 0;
    char name[50];
    char address[100];
    int key = 0;
    do{
    printf("\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n", "1. Create a linked list", "2. Insert an item at the beginning",
    "3. Insert an item at the end", "4. Search an item based on age", "5. Reverse the list", "6. Print the list", "0. Exit");
    scanf("%d", &choice);
    switch(choice){
        case 1: sampleLinkedList();
        break;

        case 2: input(&age, &yearsOfExperience, name, address);
        push(&head, age, name, address, yearsOfExperience);
        break;

        case 3: input(&age, &yearsOfExperience, name, address);
        append(&head, age, name, address, yearsOfExperience);
        break;

        case 4:
        printf("\nEnter the age to be searched: ");
        scanf("%d", &key);
        int index = search(head, key, 0);
        if(index==-1){
            printf("Element not found");
        }
        else{
            printf("Element found at position %d", index+1);
        }
        break;

        case 5: reverse(&head);
        printList(head);
        break;

        case 6: printList(head);
        break;

        case 0: exit(0);
        break;

        default: "You've entered a wrong number";

    }

    }while(choice!=0);
    return 0;
}