ELI5: c++ parameters

In everyday life, parameters are like the specific ingredients or instructions you give someone so they can complete a task for you.

Imagine you have a friendly robot chef at home. If you just tell the robot, "Bake!", it will get confused because it does not know what to make. Instead, you have to give it details, like "chocolate" and "ten minutes." Those extra details are the parameters. They fill in the blanks so the job can be done properly.

In C++, actions are like recipes, and parameters are the empty slots waiting for information. There are two main ways to share this information:

• Passing by value (The Photocopier): Imagine you have a secret family cookie recipe written on a card. Instead of handing over your real card, you make a photocopy and give that to your friend. If your friend accidentally spills milk on their copy or scribbles on it, your original recipe safe at home is completely untouched. You gave them the value, not the actual item.
• Passing by reference (The Original Notebook): Now imagine you hand your friend your actual, original notebook. If they cross out a word or add sprinkles to the page, your real notebook changes forever. You gave them direct access to your real object, meaning any changes they make stay made.
• Constant reference (Look, but do not touch): This is like placing your original recipe inside a glass picture frame. Your friend can look at it to bake the cookies, but the glass stops them from ever writing on it or changing your words. It is fast because you did not need to make a copy, but it is also completely safe.