Explain the term "dynamic memory allocation" in C++?
Please explain it in such a way i will understand it
when your program loads and runs, it occupies a certain amount of memory, for instructions, data storage, etc. As it runs, it may need additional memory space to store more data, or load new instructions.
So, one of the system subroutines is a call to malloc or some equivalent function, which contacts the operating system and requests a new chunk of memory for program use.
This is dynamic allocation, as opposed to the static amount allocated when the program started.
It's not unique to C++. Any modern programming language has some way to grab more memory as it is needed.
Thank you so much
Dynamic memory allocation in C++ refers to the process of allocating memory at runtime for storing data. In simpler terms, it is a way to request memory from the operating system when you don't know the exact amount of memory you will need in advance.
In C++, there are two primary ways to allocate memory: stack allocation and dynamic allocation. Stack allocation is used for variables with a known size and lifespan, like integers or characters. On the other hand, dynamic memory allocation is used when you need to allocate memory for variables whose size or lifespan isn't known at compile-time.
The key concept behind dynamic memory allocation is the use of pointers. A pointer is a variable that holds the memory address of another variable. By using pointers, you can dynamically allocate memory and then manipulate the memory through the pointer.
The C++ language provides two essential operators for dynamic memory allocation: `new` and `delete`. Here's a step-by-step explanation of how dynamic memory allocation works:
1. Declaring a pointer: Start by declaring a pointer variable of the desired data type. For example, if you want to allocate memory for an integer, you would declare a pointer like this: `int* ptr;`
2. Allocating memory: Use the `new` operator followed by the data type to allocate memory dynamically. For instance, to allocate memory for a single integer, you would write: `ptr = new int;` This statement requests memory from the operating system to hold an integer and assigns the address of that memory to the pointer variable `ptr`.
3. Storing data: Now that you have allocated memory, you can store values in it. You can access the dynamically allocated memory through the pointer using the dereference operator (*) to assign a value. For example, `*ptr = 42;` assigns the value 42 to the dynamically allocated memory.
4. Releasing memory: After you finish using the dynamically allocated memory, it is essential to release it back to the operating system to avoid memory leaks. Use the `delete` operator to deallocate the memory. For example, `delete ptr;` frees the memory previously allocated.
Dynamic memory allocation is valuable when you need to deal with data structures of unknown sizes, such as arrays, linked lists, or dynamic objects. It allows programs to efficiently manage memory resources and adapt to runtime requirements. However, it requires careful handling to avoid memory leaks or accessing deleted memory, so it's crucial to use it wisely.