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Understanding Memory Layout of Structs | Structs and Memory
C Structs
course content

Contenido del Curso

C Structs

C Structs

1. Introduction to Structs
2. Pointers and Structs
3. Structs and Memory
4. Advanced Structs Usage
5. Implementing Data Structures

bookUnderstanding Memory Layout of Structs

Memory structures in the C programming language play a key role in understanding how data is stored and accessed in memory. When a structure is defined in C, the compiler determines how to place its members in memory based on alignment and padding rules.

Here's an overview of how basic memory allocation for structures works in C:

main

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123456789101112131415
#include <stdio.h> // simple struct struct Test { char x; // 1 byte int y; // 4 bytes }; int main() { struct Test example; printf("Size of struct Point: %zu\n", sizeof(example)); printf("Address of p.x (char): %p\n", &example.x); printf("Address of p.y (int): %p\n", &example.y); return 0; }

As expected, such a structure should occupy 5 bytes: 1 byte for int x, 4 bytes for int y, but this will be 8 bytes.

Why is the size of the structure much larger than we expected?

This occurs because the compiler can insert padding between members to ensure that each member begins at an address that is a multiple of its size.

Tarea

  1. Create a structure with four char fields;
  2. Initialize the structure and display its size in bytes;
  3. Display the address of each field.

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¿Todo estuvo claro?

¿Cómo podemos mejorarlo?

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Sección 3. Capítulo 1
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bookUnderstanding Memory Layout of Structs

Memory structures in the C programming language play a key role in understanding how data is stored and accessed in memory. When a structure is defined in C, the compiler determines how to place its members in memory based on alignment and padding rules.

Here's an overview of how basic memory allocation for structures works in C:

main

copy
123456789101112131415
#include <stdio.h> // simple struct struct Test { char x; // 1 byte int y; // 4 bytes }; int main() { struct Test example; printf("Size of struct Point: %zu\n", sizeof(example)); printf("Address of p.x (char): %p\n", &example.x); printf("Address of p.y (int): %p\n", &example.y); return 0; }

As expected, such a structure should occupy 5 bytes: 1 byte for int x, 4 bytes for int y, but this will be 8 bytes.

Why is the size of the structure much larger than we expected?

This occurs because the compiler can insert padding between members to ensure that each member begins at an address that is a multiple of its size.

Tarea

  1. Create a structure with four char fields;
  2. Initialize the structure and display its size in bytes;
  3. Display the address of each field.

Switch to desktopCambia al escritorio para practicar en el mundo realContinúe desde donde se encuentra utilizando una de las siguientes opciones
¿Todo estuvo claro?

¿Cómo podemos mejorarlo?

¡Gracias por tus comentarios!

Sección 3. Capítulo 1
toggle bottom row

bookUnderstanding Memory Layout of Structs

Memory structures in the C programming language play a key role in understanding how data is stored and accessed in memory. When a structure is defined in C, the compiler determines how to place its members in memory based on alignment and padding rules.

Here's an overview of how basic memory allocation for structures works in C:

main

copy
123456789101112131415
#include <stdio.h> // simple struct struct Test { char x; // 1 byte int y; // 4 bytes }; int main() { struct Test example; printf("Size of struct Point: %zu\n", sizeof(example)); printf("Address of p.x (char): %p\n", &example.x); printf("Address of p.y (int): %p\n", &example.y); return 0; }

As expected, such a structure should occupy 5 bytes: 1 byte for int x, 4 bytes for int y, but this will be 8 bytes.

Why is the size of the structure much larger than we expected?

This occurs because the compiler can insert padding between members to ensure that each member begins at an address that is a multiple of its size.

Tarea

  1. Create a structure with four char fields;
  2. Initialize the structure and display its size in bytes;
  3. Display the address of each field.

Switch to desktopCambia al escritorio para practicar en el mundo realContinúe desde donde se encuentra utilizando una de las siguientes opciones
¿Todo estuvo claro?

¿Cómo podemos mejorarlo?

¡Gracias por tus comentarios!

Memory structures in the C programming language play a key role in understanding how data is stored and accessed in memory. When a structure is defined in C, the compiler determines how to place its members in memory based on alignment and padding rules.

Here's an overview of how basic memory allocation for structures works in C:

main

copy
123456789101112131415
#include <stdio.h> // simple struct struct Test { char x; // 1 byte int y; // 4 bytes }; int main() { struct Test example; printf("Size of struct Point: %zu\n", sizeof(example)); printf("Address of p.x (char): %p\n", &example.x); printf("Address of p.y (int): %p\n", &example.y); return 0; }

As expected, such a structure should occupy 5 bytes: 1 byte for int x, 4 bytes for int y, but this will be 8 bytes.

Why is the size of the structure much larger than we expected?

This occurs because the compiler can insert padding between members to ensure that each member begins at an address that is a multiple of its size.

Tarea

  1. Create a structure with four char fields;
  2. Initialize the structure and display its size in bytes;
  3. Display the address of each field.

Switch to desktopCambia al escritorio para practicar en el mundo realContinúe desde donde se encuentra utilizando una de las siguientes opciones
Sección 3. Capítulo 1
Switch to desktopCambia al escritorio para practicar en el mundo realContinúe desde donde se encuentra utilizando una de las siguientes opciones
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