Dynamic Memory Allocation In C | C Memory Management Explained | C For Beginners | Simplilearn
Summary
TLDRThis educational video by Simply Learn introduces memory management in C programming. It explains the difference between static and dynamic memory allocation, emphasizing the flexibility of the latter for runtime memory needs. The video covers functions like malloc, calloc, realloc, and free from the stdlib.h library, illustrating how they allocate, initialize, resize, and deallocate memory blocks. Practical examples and syntax are provided, along with a simple program demonstration, ensuring viewers grasp the concepts for efficient memory usage in C.
Takeaways
- 😀 Memory management in C involves strategies for allocating and deallocating memory during the program's execution.
- 📚 There are two primary methods for memory allocation in C: static memory allocation and dynamic memory allocation.
- 🔧 Static memory allocation assigns memory to variables at compile time with a fixed size that cannot be changed.
- 💾 Dynamic memory allocation occurs at runtime, allowing for more flexibility as memory can be allocated and deallocated as needed.
- 🔑 The C standard library provides functions like `malloc`, `calloc`, `realloc`, and `free` for dynamic memory management.
- 📝 The `malloc` function is used to allocate a single block of memory, and it returns a pointer to the beginning of the block.
- 🔑 The `calloc` function allocates memory for an array, initializing all elements to zero, and requires two arguments: number of elements and size of each element.
- 🔄 The `realloc` function is used to resize a previously allocated block of memory without losing the original data.
- 🗑️ The `free` function is essential for deallocating memory that is no longer needed, making it available for other programs to use.
- 💻 The video includes a practical demonstration of using these functions, highlighting the importance of checking for memory allocation success and proper memory deallocation.
Q & A
What is memory management in C programming?
-Memory management in C programming refers to the process of allocating and deallocating memory during runtime to manage the memory more efficiently. It involves allocating memory dynamically to variables whose size is not known until runtime.
What are the two ways to allocate memory in C?
-The two ways to allocate memory in C are static memory allocation and dynamic memory allocation. Static allocation happens during compile time, while dynamic allocation occurs during runtime.
How does static memory allocation differ from dynamic memory allocation?
-In static memory allocation, the memory is allocated during compile time and the size is fixed, whereas in dynamic memory allocation, memory is allocated during runtime and its size can change as needed.
What functions are provided by C for dynamic memory allocation?
-C provides the functions malloc(), calloc(), realloc(), and free() for dynamic memory allocation. These functions are defined in the stdlib.h header file.
What is the purpose of the malloc() function in C?
-The malloc() function is used to allocate a block of memory of a specified size. It returns a pointer to the beginning of the block, which can be used to access the allocated memory.
How does the calloc() function differ from the malloc() function?
-The calloc() function is similar to malloc() but it allocates memory for an array of elements, initializing all of them to zero. It takes two arguments: the number of elements and the size of each element.
What is the role of the realloc() function in memory management?
-The realloc() function is used to resize a previously allocated block of memory. It can be used to either increase or decrease the size of the memory block without losing the existing data.
Why is the free() function necessary in C?
-The free() function is necessary to deallocate memory that was previously allocated by malloc(), calloc(), or realloc(). It helps in returning the memory back to the heap for reuse by other programs, thus preventing memory leaks.
What happens if malloc() fails to allocate memory?
-If malloc() fails to allocate memory, it returns a null pointer. It's important to check the return value to ensure that memory allocation was successful before using the allocated memory.
What is the significance of checking the return value of memory allocation functions?
-Checking the return value of memory allocation functions is significant because it allows the programmer to handle errors, such as memory allocation failure, gracefully. It prevents the program from using uninitialized memory, which can lead to crashes or undefined behavior.
Outlines
💾 Introduction to Memory Management in C
This paragraph introduces the topic of memory management in C programming. It explains the difference between static and dynamic memory allocation. Static allocation assigns memory during compile time with a fixed size, while dynamic allocation occurs at runtime and allows for variable memory sizes. The paragraph sets the stage for a deeper exploration of dynamic memory allocation, mentioning functions like malloc, calloc, realloc, and free from the stdlib.h library. It also provides a brief overview of the syntax and examples that will be covered in the video.
🔧 Practical Examples of Dynamic Memory Allocation
This paragraph delves into practical examples of using dynamic memory allocation functions in C. It demonstrates how to check for memory availability, allocate memory using malloc, and deallocate it using free. The paragraph also shows an error scenario where calloc is used with only one argument, illustrating the importance of providing the correct number of arguments. The video concludes with a successful execution of calloc after correcting the error, highlighting the output of the program. The paragraph wraps up with a call to action for viewers to subscribe and engage with the channel for more informative content.
Mindmap
Keywords
💡Memory Management
💡Static Memory Allocation
💡Dynamic Memory Allocation
💡Heap Memory
💡malloc Function
💡calloc Function
💡realloc Function
💡free Function
💡Pointer
💡Memory Leak
Highlights
Introduction to memory management in C programming.
Explanation of static memory allocation during compile time.
Discussion on dynamic memory allocation at runtime.
Difference between static and dynamic memory allocation.
Efficient memory management using dynamic allocation.
Introduction to C functions for dynamic memory allocation: malloc, calloc, realloc, and free.
Syntax and example of the malloc function.
How malloc checks for available memory and returns a pointer.
Syntax and example of the calloc function for allocating memory with zero-initialized values.
Explanation of the realloc function for resizing memory blocks.
Use case of realloc when needing to change array size without data loss.
Syntax and example of the free function for deallocating memory.
Importance of freeing memory to allow other programs to use it.
Running a simple program to demonstrate memory allocation and deallocation.
Error handling when using calloc with incorrect arguments.
Conclusion and summary of the session on C memory management.
Call to action for subscribing to the Simply Learn YouTube channel.
Transcripts
hey guys welcome to yet another
interesting and informative video by
simply learn in today's video we're
gonna be learning all about memory
management insane but before we begin if
you haven't subscribed to our channel
already make sure to hit the subscribe
button and the bell icon to never miss
an update so now without any further
delay let's begin
this session will help you to understand
what is memory management in c
later we will discuss dynamic memory
allocation and function used to allocate
memory dynamically with the help of
syntax and examples
so now let's begin with what memory
management in c is
as we all know in c programming the
memory is automatically allocated to all
the program variables during compile
time
so sometimes to reallocate the memory or
to change the size of an array we must
allocate memory during runtime and we
have two ways to locate memory
and they are static memory allocation
and dynamic memory allocation
in static memory allocation the memories
are located during compile time and the
fixed size of memory will be assigned to
the variables
moreover there won't be any change in
the memory size and location and in the
case of dynamic memory allocation the
memories are located during runtime
so now let us try to understand more
about dynamic memory allocation
to manage the memory more efficiently we
use dynamic memory allocation
unlike static allocation the memories
are located during run time in dynamic
memory allocation
and the allocated memory is not constant
or fixed we can allocate the memory
blocks from the hip whenever required
when the memory block is no longer in
use we can also return the block of
memory to the hip for reuse by another
program
and in addition to this we can also
reallocate the block of memory space
when required to allocate memory
dynamically c provides a set of
functions and they are emblock clock
reallock and free functions that are
defined in the stdlib dot hedge that is
standard library header file
let's look at the syntax and examples of
this function
first when we use the mlog function the
continuous block of memory will be
allocated and the point of variable will
hold the address of the first element
now let's look at the below given syntax
the mlog function take one argument
memory size for example
if we require 10 bytes of memory size we
can mention 10 or we can mention the
size of int
the mlog function will first checks
whether the continuous memory is
available on the hip and if free memory
is unavailable the function will return
a 0 or a null value
else it will allocate the memory as per
the requested size if memory is
available
and the pointer will point to the
address of the first element in the
block
next we have clock function
the syntax is pointer variable is equal
to c log of number element comma memory
size for example we have 10 as a number
element and the element size is the size
of int
clr function is similar to the mlog
function but in case of clr function
multiple blocks of memory of the same
size will be allocated which holds 0
value by default and it takes 2
arguments that is number element and
element size
up next we have reallock function
first let us look at the syntax
pointer variable is equal to reallock
pointer variable comma memory size
in real lock function we pass point of
variable as an argument and the memory
size for example
real lock pointer variable ptr comma the
size of it
so sometimes it becomes very difficult
to change the array size when we have to
store new values into the array or to
copy into the larger size array so in
that case we use real log functions to
change the array size without losing the
data in short the real of function will
change the size of the previously
allocated block of memory
i hope you got a good understanding of
why we use real log function
moving ahead we have free function
syntax is simple we pass pointer in free
function like for example free ptr the
free function is used to deallocate the
memory space occupied by the previously
allocated by mlog c a lock or rear lock
functions
in order to use the memory more
efficiently and to return back the
memory to the hip once done we use free
function
once we free the memory other programs
can use that block of memory if required
now let's run simple program using this
function
so in this particular example we have
included the standard library header
file
that is stdlib.h and then mlog function
and using if condition we're gonna check
whether memory is available or not and
if memory is available it gonna locate
the memory and print the value of 10.
and finally we have used free function
to deallocate the memory so now let's
run it
as you all can see the value 10 is
printed successfully
now using same program let's use clock
function so instead of mlog let's give
cllo
and since we have passed only one
argument that is sizeof end let's
execute the program and see what would
be the
error as you can see the error
it says that too few arguments to
function see alok
it means that the clock function will
take two arguments so let's give the
number element
so save the program
and
run it
and here we got the output
so with this we have come to the end of
this session on c memory management i
hope this session was informative and
interesting until next time thank you
stay safe and keep learning
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