question2.c

#define _CRT_SECURE_NO_WARNINGS

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

#define STR_MAX_LEN 20

typedef struct personNode {
    char name[STR_MAX_LEN];
    int age;

    struct personNode* next;
} personNode;

void myFgets(char str[], int n);
void printList(personNode* head);
void freeList(personNode* head);
void insertAtEnd(personNode** head, personNode* newNode);
int listLength(personNode* head);
personNode* createPersonNode();
personNode* getList(personNode* head, int size);
personNode* copyList(personNode* head);


int main()
{
    int peoples_number = 0;
    personNode* head = NULL;
    personNode* duplicate = NULL;

    printf("How many people in the list? ");
    scanf("%d", &peoples_number);
    getchar();

    head = getList(head, peoples_number);
    printList(head);

    printf("List length: %d\n", listLength(head));

    duplicate = copyList(head);
    printf("New list:\n");
    printList(duplicate);

    freeList(head);
    freeList(duplicate);

    getchar();
    return 0;
}
/* Inserts the given node into the end of the head (main) node
* input: head of the main node, new node
* output: -
*/
void insertAtEnd(personNode** head, personNode* newNode)
{
    if (!*head)
    {
        *head = newNode;
    }
    else
    {
        personNode* p = *head;
        while (p->next)
        {
            p = p->next;
        }
        p->next = newNode;
    }
}
/* Creates new node of person
* input: -
* output: new node of person struct type
*/
personNode* createPersonNode()
{
    personNode* newPersonNode = (personNode*)malloc(sizeof(personNode));
    strcpy(newPersonNode->name, "No name");
    newPersonNode->age = 0;
    newPersonNode->next = NULL;

    return newPersonNode;
}
/* Custom fgets with built-in '\n' remove
* input: string to in-put, string size
* output: -
*/
void myFgets(char str[], int n)
{
    fgets(str, n, stdin);
    str[strcspn(str, "\n")] = 0;
}
/* Prints the given list
* input: head of the main node (list)
* output: -
*/
void printList(personNode* head)
{
    personNode* current_node = head;

    while (current_node != NULL)
    {
        printf("Name: %s, Age: %d\n", current_node->name, current_node->age);
        current_node = current_node->next;
    }
}
/* Counts the length of the given list
* input: head of the main node (list)
* output: length of the given list
*/
int listLength(personNode* head)
{
    if (!head)  // if list empty
    {
        return 0;
    }
    else
    {
        return 1 + listLength(head->next);
    }
}
/* Return duplicate of the given list
* input: head of the main node (list)
* output: NEW; ALLOCATED in memory list duplicate of the given 'head' node (list)
*/
personNode* copyList(personNode* head)
{
    if (!head)  // if list empty
    {
        return NULL;
    }
    else
    {

        // Allocate the memory for new Node
        // in the heap and set its data
        personNode* newNode = (personNode*)malloc(sizeof(personNode));

        strcpy(newNode->name, head->name);
        newNode->age = head->age;

        // Recursively set the next pointer of
        // the new Node by recurring for the
        // remaining nodes
        newNode->next = copyList(head->next);

        return newNode;
    }
}
/* Asks the user to input the name and age according the given number of peoples
* input: head of the main node, number of peoples
* output: new node of personNode struct type
*/
personNode* getList(personNode* head, int size)
{
    int i = 0;
    personNode* newNode = NULL;

    for (i = 0; i < size; i++)
    {
        newNode = createPersonNode();

        printf("Enter name: ");
        myFgets(newNode->name, STR_MAX_LEN);

        printf("Enter age: ");
        scanf("%d", &(newNode->age));
        getchar();

        insertAtEnd(&head, newNode);
    }

    return head;
}
/* Frees the memory that the node used
* input: the head of the main node (list)
* output: -
*/
void freeList(personNode* head)
{
    personNode* tmp;

    while (head)
    {
        tmp = head;
        head = head->next;
        free(tmp);
    }
}