What happens if you define a function but do not call it?

When you define a function in a programming language, you create a reusable block of code that can perform a specific task. If you do not call the function after defining it, the function remains in memory as a defined entity, but it does not execute any of its instructions. This means that while the programming environment recognizes the function and can retain it for potential future use, all of the code within that function will not run unless explicitly invoked.

This behavior allows for greater flexibility, as you can define a function once and call it multiple times later in your code whenever needed without rewriting the same block of code. If a function is never called within the program, it simply sits idle in memory waiting for a call that may never come. The program itself will still compile as long as the function is defined correctly.