What is the main purpose of a variable in C++?

The main purpose of a variable in C++ is to store data values that can be used and manipulated within a program. Variables act as named storage locations in memory that hold data. By assigning a value to a variable, you can easily retrieve or modify that value throughout the program. This allows for dynamic data handling, where the content of variables can change as the program runs.

For instance, if you declare a variable to hold a number, you can perform various operations with it, such as arithmetic calculations or conditional checks, making it a fundamental concept in programming. This flexibility to store different types of data (like integers, floats, characters, etc.) and modify them during the execution of the program is what makes variables essential for developing algorithms and managing data flow.

The other choices, while related to programming concepts, do not accurately reflect the primary function of a variable. Functions are stored and executed separately; input/output operations are handled through specific statements and libraries, and memory management involves additional concepts beyond just variable declaration and usage.