CompTIA ITF+ Practice Test

A pointer is a variable that holds the memory address of another variable. While it can be used to indirectly access and change the value of a variable, it is not the most efficient or common method for simply storing and updating a changing number.

A function is a block of code that performs a specific task. While functions can be used to manipulate and update the value of a variable, their primary purpose is to execute a specific action rather than to store a value.

An algorithm is a step-by-step procedure for solving a specific problem. It is a sequence of instructions that can be followed to achieve a desired result. While algorithms may use variables as part of their steps, they are not used specifically for storing changing values.

A variable is a named location in a computer's memory that holds a value. In this scenario, Joe would most likely use a variable to store the number that changes over the program's duration. By assigning a value to a variable and using it throughout the program, Joe can easily update and access the changing number as needed. Therefore, a variable would be the most likely choice for Joe to use in this scenario.