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C Structs

1. Introduction to Structs

What are Structs Structs Application Defining and Declaring Structs Creating Your First Struct Accessing Struct Fields

2. Pointers and Structs

Pointers Brief Overview Pointers to Structs Pointers Inside Structs Dynamically Allocating Structs Passing Structs to the Functions

3. Structs and Memory

Understanding Memory Layout of Structs Alignment and Padding in Structs Unions Arrays with Structs

4. Advanced Structs Usage

Nested Structs Struct with Arrays and Other Structs Anonymous Struct and Union Complex Data Structure

5. Implementing Data Structures

Introduction to Linked List Basic Concept and Structure Building a Linked List Travesting and Displaying Linked List Completion Overview

Dynamically Allocating Structs

Let's review how to dynamically allocate memory in the C language.

To allocate memory on the heap, use the malloc() function from the stdlib.h library:

Note
When you dynamically allocate memory for use in your program, that memory remains reserved until you explicitly free it using free().

main


              12345678910111213141516171819
            
#include <stdio.h>
#include <stdlib.h>

// structure definition
struct Example {
    int someValue[20]; // int = 4 bytes, 20 * 4 = 80 bytes
};

int main() {
    // allocating memory for Example structure
    struct Example* pExample = (struct Example*)malloc(sizeof(struct Example));

    printf("Allocating memory = %zu bytes\n", sizeof(*pExample));

    // freeing memory
    free(pExample);
    
    return 0;
}

If a structure contains several fields of different data types, the compiler will equalize the size of the fields so that the structure is "conveniently" stored in memory.

After the completed job, pay attention to how many bytes are allocated for the structure with the int and char fields. This phenomenon will be discussed later in this course.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Перейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів

Все було зрозуміло?

Секція 2. Розділ 4

Dynamically Allocating Structs

Let's review how to dynamically allocate memory in the C language.

To allocate memory on the heap, use the malloc() function from the stdlib.h library:

Note
When you dynamically allocate memory for use in your program, that memory remains reserved until you explicitly free it using free().

main


              12345678910111213141516171819
            
#include <stdio.h>
#include <stdlib.h>

// structure definition
struct Example {
    int someValue[20]; // int = 4 bytes, 20 * 4 = 80 bytes
};

int main() {
    // allocating memory for Example structure
    struct Example* pExample = (struct Example*)malloc(sizeof(struct Example));

    printf("Allocating memory = %zu bytes\n", sizeof(*pExample));

    // freeing memory
    free(pExample);
    
    return 0;
}

If a structure contains several fields of different data types, the compiler will equalize the size of the fields so that the structure is "conveniently" stored in memory.

After the completed job, pay attention to how many bytes are allocated for the structure with the int and char fields. This phenomenon will be discussed later in this course.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Все було зрозуміло?

Секція 2. Розділ 4

Dynamically Allocating Structs

Let's review how to dynamically allocate memory in the C language.

To allocate memory on the heap, use the malloc() function from the stdlib.h library:

Note
When you dynamically allocate memory for use in your program, that memory remains reserved until you explicitly free it using free().

main


              12345678910111213141516171819
            
#include <stdio.h>
#include <stdlib.h>

// structure definition
struct Example {
    int someValue[20]; // int = 4 bytes, 20 * 4 = 80 bytes
};

int main() {
    // allocating memory for Example structure
    struct Example* pExample = (struct Example*)malloc(sizeof(struct Example));

    printf("Allocating memory = %zu bytes\n", sizeof(*pExample));

    // freeing memory
    free(pExample);
    
    return 0;
}

If a structure contains several fields of different data types, the compiler will equalize the size of the fields so that the structure is "conveniently" stored in memory.

After the completed job, pay attention to how many bytes are allocated for the structure with the int and char fields. This phenomenon will be discussed later in this course.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Все було зрозуміло?

Let's review how to dynamically allocate memory in the C language.

To allocate memory on the heap, use the malloc() function from the stdlib.h library:

Note
When you dynamically allocate memory for use in your program, that memory remains reserved until you explicitly free it using free().

main


              12345678910111213141516171819
            
#include <stdio.h>
#include <stdlib.h>

// structure definition
struct Example {
    int someValue[20]; // int = 4 bytes, 20 * 4 = 80 bytes
};

int main() {
    // allocating memory for Example structure
    struct Example* pExample = (struct Example*)malloc(sizeof(struct Example));

    printf("Allocating memory = %zu bytes\n", sizeof(*pExample));

    // freeing memory
    free(pExample);
    
    return 0;
}

If a structure contains several fields of different data types, the compiler will equalize the size of the fields so that the structure is "conveniently" stored in memory.

After the completed job, pay attention to how many bytes are allocated for the structure with the int and char fields. This phenomenon will be discussed later in this course.

Завдання

Create a pointer variable and allocate memory for your structure;
Display the size of structure;
Fill the fields and display the content of your structure;
Free up the allocated memory;
Displaying the values again.

Секція 2. Розділ 4