What is a pointer in programming?

A pointer in programming is fundamentally defined as a variable that stores the memory address of another variable. This concept is crucial in various programming languages, particularly those that allow direct memory manipulation, such as C and C++. By holding the address, pointers enable efficient data access and manipulation, allowing programmers to work with arrays, dynamic memory, and even functions.

For instance, using pointers can help in passing large structures or arrays to functions without copying the actual data, thus improving performance. Pointers also facilitate the creation of complex data structures like linked lists and trees, where elements are connected via memory addresses rather than direct indexes. Understanding pointers is essential for effective memory management and manipulation in programming practices.