Week 7 Code Examples

list/list.c

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

struct node *create_node(int num) {
    struct node *new_node = malloc(sizeof(struct node));

    // *, *my_num <- deferencing the pointer to get the value of it
    // (*new_node).data 
    new_node->data = num;
    new_node->next = NULL;

    return new_node;
}

void print_list(struct node *head) {
    struct node *current = head;

    if (head == NULL) {
        printf("The list is empty!\n");
        return;
    }

    while (current != NULL) {
        printf("The node's data is %d\n", current->data);
        current = current->next;
    }
}

struct node *insert_head(struct node *head, int num) {
    struct node *new_node = create_node(num);
    
    new_node->next = head;
    head = new_node;

    return head;
}

struct node *insert_tail(struct node *head, int num) {
    struct node *current = head;
    struct node *new_node = create_node(num);

    if (head == NULL) {
        head = new_node;
        return head;
    }

    while (current->next != NULL) {
        current = current->next;
    }

    current->next = new_node;

    return head;
}

struct node *insert_nth(struct node *head, int num, int n) {
    if (head == NULL) {
        struct node *new_node = create_node(num);
        head = new_node;
        return head;
    }

    // insert at the head
    if (n <= 0) {
        head = insert_head(head, num);
        return head;
    }

    int count = 1;
    struct node *current = head;

    while (count != n && current->next != NULL) {
        current = current->next;
        count++;
    }

    struct node *new_node = create_node(num);
    new_node->next = current->next;
    current->next = new_node;

    return head;
}

list/list.h

struct node {
    int data;
    struct node *next;
};

// Function that mallocs and returns a new node
// Params:
//      - num: data for the node
// Returns:
//      - pointer to a struct node
struct node *create_node(int num);

// FUnction to print a linked list
// Params: 
//      - head: a pointer to teh first node in the list
// Return:
//      nothing
void print_list(struct node *head);

// Function that inserts a node into the head of a linked list
struct node *insert_head(struct node *head, int num);

// Function to insert a node at the tail of the list
// Params:
//      - head: pointer to the head of the list
//      - num: the dnode data we weant to insert
// Returnbs:
//      - head: a pointer to the head of the list
struct node *insert_tail(struct node *head, int num);

// Function to inser at the nth position of a list
// Params:
//      - head: a pointer to the first node in the list
//      - num: the niode data we want to insert into the list
//      - n: the position we want to insert into our list at, 1-indexed
// Return:
//      - head: a pointer to the head od the list
struct node *insert_nth(struct node *head, int num, int n);

list/main.c

#include <stdio.h>
#include "list.h"

int main(void) {

    struct node *head = NULL;

    head = insert_head(head, 1);

    head = insert_head(head, 3);

    head = insert_head(head, 5);

    head = insert_tail(head, -1);

    head = insert_nth(head, 10, 2);

    head = insert_nth(head, 6, -2);

    head = insert_nth(head, 7, 100);

    head = insert_nth(head, 15, 7);

    print_list(head);

    return 0;
}

malloc.c

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

struct node {
    struct    node *next;
    int data;
};

struct test {
    int num1;
    int num2;
    int num3;
};

int main(void) {

    int array[10] = {0};
    struct node new_node;

    struct test test2;

    printf("The size of an int is %lu\n", sizeof(int));
    printf("The size of an double is %lu\n", sizeof(double));
    printf("The size of an char is %lu\n", sizeof(char));

    printf("The size of 10 int is %lu\n", 10 * sizeof(int));
    printf("The size of the array is %lu\n", sizeof(array));

    printf("The size of struct node is %lu\n", sizeof(new_node));
    printf("The size of the struct test is %lu\n", sizeof(test2));

    int *my_ptr_int = malloc(sizeof(int));

    // printf("%p\n", my_ptr_int);

    *my_ptr_int = 6;

    printf("%d\n", *my_ptr_int);

    free(my_ptr_int);

    // printf("%d\n", *my_ptr_int);

    return 0;
}

maths/main.c

#include <stdio.h>

#include "maths.h"

int main(void) {

    int area = rect_area();

    printf("The area is: %d\n", area);

    double c_area = circle_area();
    
    printf("The area is: %lf\n", c_area);

    return 0;
}

maths/maths.c

#include <stdio.h>
#include "maths.h"

int rect_area(void) {
    int height;
    int width;

    int area;

    printf("Enter the width and height of the rectangle: ");
    scanf("%d %d", &height, &width);

    area = height * width;

    return area;
}

double circle_area(void) {
    double radius;
    printf("Enter the radius of the circle: ");

    scanf("%lf", &radius);

    double area = PI * (radius * radius);

    return area;
}

maths/maths.h

#include <stdio.h>

#define PI 3.141592653589

// This function calculates the area of a rectangle
// it scans in a height and width and returns the result
int rect_area(void);


// THis function calculates teh area of a circle
// in scans in a radius and resturns the result
double circle_area(void);

struct_pointer.c