Explain when and why should you create functions?

 If you just want to use the function in your program, you don't have to know how it works inside! You don't have to understand anything about what goes on inside the function.

It's sort of like driving a car or using a telephone. With an automobile, you don't need to understand every detail about the engine and drive train and wheels, if all you want to do is drive the car. Similarly, with a telephone, you don't have to understand everything about the phone system in order to make a call.

The only time you need to know how a function works inside is when you need to write the function, or change how it works. It's like a car again; you need to know how a car works in order to build one or fix one. But once a function is written and working, you never need to look at its insides again.

Hope this helps, 

kwrob

answerthey protect the head and neck in rear impacts;