Parameter validation

Imagine you're playing with your toys and your Mom asks you to pick up your little sister's toys before you go outside to play. You want to make sure you do a good job, so you ask your Mom, "Which toys do I need to pick up?" Your Mom tells you that you only have to pick up toys that belong to your sister, not yours or your brother's.

That's kind of like parameter validation. When someone is writing a computer program, they need to make sure that the information they're using is correct and safe. They don't want to accidentally use the wrong information or let someone else sneak in and use the program wrong. So, they create rules (like your Mom did) to make sure that the information going into the program is what it's supposed to be.

These rules are called parameter validation. They help make sure that the information coming into the program is safe and accurate. It's like making sure you only pick up your sister's toys and not accidentally take one of your own. By doing this, the computer program can work properly and give the right results.