14.Implement Linear Linked List.

//Program to implement Linear Linked List.
#include <stdio.h>
#include <malloc.h>
#include <conio.h>

struct student {
    char name[20];
    struct student *next;
} *first = NULL, *last, *temp;

void insert() {
    temp = (struct student *) malloc(sizeof(struct student));

    printf("Enter name: ");
    scanf("%s", temp->name);

    temp->next = NULL;

    if (first == NULL) {
        first = temp;
        last = temp;
        printf("Created first node.");
        getch();
    } else {
        last->next = temp;
        last = temp;
        printf("Inserted new node.");
        getch();
    }
}

void display() {
    temp = first;

    while (temp != NULL) {
        printf("%s\n", temp->name);
        temp = temp->next;
    }
    getch();
}

void search() {
    char name[20];
    int count = 1;

    printf("Enter name to search: ");
    scanf("%s", name);

    temp = first;

    while (temp != NULL) {
        if (!strcmp(name, temp->name)) {
            printf ("Match found at node %d.", count);
            getch();
            break;
        }
        count++;
        temp = temp->next;
    }

    if (temp == NULL) {
        printf("Match not found.");
        getch();
    }
}

void erase() {
    if (first->next == NULL) {
        printf("The list cannot be empty.");
        getch();
        return;
    }
    temp = first;
    first = first->next;
    free(temp);

    printf("Deleted first node.");
    getch();
}

void main()
{
    char choice;

    while (1) {
        clrscr();

        printf("1.Insert node\n2.Display list\n3.Search node\n4.Delete node\n5.Exit\n\n");
        choice = getch();

        switch (choice) {
            case '1':
            insert();
            break;

            case '2':
            display();
            break;

            case '3':
            search();
            break;

            case '4':
            erase();
            break;

            case '5':
            return;

            default:
            printf("Invalid input.");
            getch();
        }
    }
}