External variable

An external variable is like a toy that everyone can play with. Let's say you have a toy car and you want to play with it, but your friend also wants to play with it. You can let your friend play with it, right? That's kind of like what an external variable is. It's a toy (in the world of computer programs) that everyone can use and change.

So let's say you have a computer program, and you want to use a number in it. You can create a variable and set it equal to that number. That variable is yours to use and change within that program. But let's say you have another program that also needs to use that same number. You could make another variable in that program, but it would be a separate thing from the first variable.

That's where an external variable comes in. It's like a variable that everyone can see and use. It's like passing around a toy car so that everyone can play with it. So if you make a variable external, it means that it can be used and changed by any program that needs it. It's like making the toy car available to your friends so that they can all play with it too.

But be careful! Just like with a toy car, if too many people try to play with it at the same time, it might get broken or not work right. Similarly, if too many programs try to use or change the same external variable at the same time, the program might not work the way it's supposed to. So it's important to use external variables responsibly and make sure that everyone who uses them knows what they're doing.