My Understanding of an API

[John_Developer]

Hi everyone,

im very new at all this so please understand if im not yet giving good examples but ill try my best.

I have tried to make sense of what an API actually is, from what ive read, the Application Programming Interface (API) is a package of code that is hidden from us and ran on the execution layer which directly communicates with the Operating System to carry out processes.

For example, if im developing a small program in VB.NET, a simple form with a button that says "Hello" once clicked, does that mean I have effectivly created an API that does this action? or is the API actually the code that works in the background to make this happen and make my message come up on the screen?

Im still not clear on it all, im just after some very basic examples without gettign too bogged down in the actually nitty gritty.
EDIT**

Also, i heard somewhere that all APIs are web based? .. is that rubbish? .. for example an API is for a web based service, well then how ca nthey run on my computer if they are web based? I dont think that they are, but we will see.

Thanks for reading.

John

 

[Menthos]

You'll see the term API used in a whole host of situations and, no, it's not something that's only relevant to web based apps.

For example, a third party library of classes that you might use in your own code would likely have a number of public and private methods - you could describe the public methods you use to get functionality out of the classes as an API... an Interface between your code and the third party library.

I'm sure you've checked the wikipedia entry for the term - if not, it should help.