A cast operator is a programming tool used to convert a variable from one data type to another. For example, in languages like C++ or Java, you might use a cast operator to change an integer to a floating-point number. This is useful when you need to perform operations that require specific data types, ensuring that the program runs correctly and efficiently. There are two main types of casting: implicit and explicit. Implicit casting happens automatically when the compiler converts a smaller data type to a larger one, like converting an int to a double. Explicit casting, on the other hand, requires the programmer to specify the conversion, often using parentheses, to avoid potential data loss or errors.