In C++, the `new` keyword is used to dynamically allocate memory for objects and data structures at runtime. When used with a data type, it allocates memory for a single object of that type and returns a pointer to the allocated memory.
For example:
int* ptr = new int; // Dynamically allocate memory for an integer
In this example, `ptr` is a pointer to an integer, and `new int` allocates memory for an integer on the heap and returns a pointer to that memory, which is then assigned to `ptr`.
We can also use `new` to allocate memory for arrays:
Example:
int* arr = new int[10]; // Dynamically allocate memory for an array of 10 integers
After allocating memory using `new`, it's essential to release this memory when it's no longer needed to prevent memory leaks. This is done using the `delete` operator:
delete ptr; // Deallocate memory allocated for a single integer
delete[] arr; // Deallocate memory allocated for an array of integers
It's important to pair `new` with `delete` for single objects and `new[]` with `delete[]` for arrays to ensure proper deallocation of memory. Failure to do so can lead to memory leaks.