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C Memory Management
What is Memory Management?
Memory management in C refers to manually controlling memory allocation and deallocation.
Unlike many languages, C does not automatically manage memory for you.
Stack vs Heap
There are two main types of memory in C:
- Stack: Automatically managed, used for local variables
- Heap: Manually managed, used for dynamic memory
malloc()
malloc() allocates memory but does not initialize it.
calloc()
calloc() allocates memory and initializes it to zero.
realloc()
realloc() resizes previously allocated memory.
free()
free() releases allocated memory back to the system.
Failing to free memory causes memory leaks.
Dynamic Arrays
You can dynamically allocate arrays using malloc or calloc.
Checking for NULL
Always check if memory allocation was successful.
Memory Leaks
A memory leak happens when allocated memory is not freed.
Dangling Pointers
A dangling pointer points to memory that has already been freed.
Best Practices
- Always free memory
- Check for NULL
- Set pointer to NULL after freeing
Real-World Example
Dynamic memory is commonly used when the size of data is not known at compile time.
Why Memory Management is Important
Memory management is one of the most important features of C.
- Efficient use of memory
- Essential for systems programming
- Used in operating systems and embedded systems
Common Mistakes
Be careful with these:
- Not freeing memory
- Using freed memory
- Incorrect memory size allocation
Practice
Dynamically allocate an array, store values, print them, and free memory.