A function pointer is a variable that stores the address of a function in programming languages like C and C++. This allows the program to call the function indirectly, enabling dynamic function calls and the ability to pass functions as arguments to other functions. Using function pointers can enhance flexibility in code, such as implementing callback functions or creating arrays of functions. They are particularly useful in scenarios like event handling or when implementing state machines, where different functions may need to be executed based on certain conditions.