Stack vs heap in embedded context - Hands-On Comparison

Understanding Stack vs Heap in Embedded C

📖 Scenario: In embedded systems, memory is limited and managing it well is very important. Two main areas where memory is used are the stack and the heap. The stack is used for temporary data like function variables, and the heap is used for dynamic memory allocation.Imagine you are programming a small embedded device that needs to store some data temporarily and also allocate memory dynamically for a buffer.

🎯 Goal: You will write a simple embedded C program that shows how to use the stack and the heap. You will create a local variable on the stack and allocate memory on the heap using malloc. Then you will print their addresses to see the difference.

📋 What You'll Learn

Create a local variable on the stack

Allocate memory dynamically on the heap using malloc

Print the addresses of the stack variable and the heap memory

Understand the difference in memory locations

💡 Why This Matters

🌍 Real World

Embedded devices like sensors and controllers have limited memory. Understanding stack and heap helps write efficient and safe programs.

💼 Career

Embedded software engineers must manage memory carefully to avoid crashes and bugs in devices like medical equipment, automotive systems, and IoT gadgets.

1

Create a local variable on the stack

Write a line of code to declare an integer variable called stack_var and set it to 10 inside the main function.

Embedded C

#include 
#include 

int main() {
    // Declare an integer variable called stack_var and set it to 10
    // Your code here
    return 0;
}

Need a hint?

Use int stack_var = 10; inside main.

2

Allocate memory dynamically on the heap

Add a line of code to allocate memory for an integer pointer called heap_var using malloc. Allocate space for one integer.

Embedded C

#include 
#include 

int main() {
    int stack_var = 10;
    // Allocate memory for an integer pointer called heap_var using malloc
    // Your code here
    return 0;
}

Need a hint?

Use int *heap_var = (int *)malloc(sizeof(int)); to allocate memory on the heap.

3

Store a value in the heap memory

Add a line of code to store the value 20 in the memory pointed to by heap_var.

Embedded C

#include 
#include 

int main() {
    int stack_var = 10;
    int *heap_var = (int *)malloc(sizeof(int));
    // Store 20 in the memory pointed to by heap_var
    // Your code here
    return 0;
}

Need a hint?

Use *heap_var = 20; to store the value in heap memory.

4

Print the addresses of stack and heap variables

Add two printf lines to print the addresses of stack_var and heap_var using %p. Then free the allocated heap memory.

Embedded C

#include 
#include 

int main() {
    int stack_var = 10;
    int *heap_var = (int *)malloc(sizeof(int));
    *heap_var = 20;
    // Print the address of stack_var
    // Print the address stored in heap_var
    // Free the allocated heap memory
    // Your code here
    return 0;
}

Need a hint?

Use printf("Address of stack_var: %p\n", (void *)&stack_var); and printf("Address of heap_var: %p\n", (void *)heap_var);. Don't forget to free(heap_var);.