Ivor Horton's Beginning Visual C++ 2012

DYNAMIC MEMORY ALLOCATION

Working with a fixed set of variables in a program can be very restrictive. You will often want to decide the amount of space to be allocated for storing different types of variables at execution time, depending on the input data for the program. Any program that involves reading and processing a number of data items that is not known in advance can take advantage of the ability to allocate memory to store the data at run time. For example, if you need to implement a program to store information about the students in a class, the number of students is not fixed, and their names will vary in length, so to deal with the data most efficiently, you’ll want to allocate space dynamically at execution time.

Obviously, because dynamically allocated variables can’t have been defined at compile time, they can’t be named in your source program. When they are created, they are identified by their address in memory, which is contained within a pointer. With the power of pointers, and the dynamic memory management tools in Visual C++, writing your programs to have this kind of flexibility is quick and easy.

The Free Store, Alias the Heap

In most instances, when your program is executed, there is unused memory in your computer. This unused memory is called the heap in C++, or sometimes the free store. You can allocate space within the free store for a new variable of a given type using a special operator in C++ that returns the address of the space allocated. This operator ...