Before we start...

We use language to conversation. What if the language is different?

 

Supposing we travel to Amazon forest, there are the small tribe. They made there own language and lived there own life.(so, they only speak their own language but nothing else)

Let’s try to make conversation with them. we may need to know their language before conversation. 

We settle down and start to learn their language. As time goes by, we are not fluent but stutter. 

Now, can you sure you know all about their language? will conversation goes well?

Why don't we use interpreter?

Fortunately there are interpreter who fluent with the tribe’s language. I think using interpreter is the best and easy way to conversation with them.

Then we can communicate with tribe using our language. Interpreter will translate what we want to say quickly and correctly to the tribe’s language. We can talk to them now!

Let’s talk to computer

Preview
1) We use programming language to talk to computer.
2) Computer can’t understand high-level language(programming language) using by human
3) Compiler can translate programming language to low-level language which computer can understand.

We compared the tribe to computer. we are going to learn about programming language to conversation with computer. Let’s think programming language is “the language” that human can conversation with computer.

There are many kinds of language that we can learn such as Java,C,C++,C#,Python.

Human can learn these kinds of language, so we can call that high-level language.

In conclusion, programmer use high-level language to talk to computer. 

Therefore, only human can understand them. The document wrote down in high-level language is “source code”(or just code).

Computer can’t understand high-level language that we talk about before.

Computer use binary notation that consist 0 and 1 called machine language(or low-level language). 

It’s difficult to understand machine language to us so, we need some process which translate low-level language to high-level language. This process called compile and this translatable program called compiler.

When compiler do not exist. 

When compiler exist.

Computer only understand low-level language that translated by compiler. 

When these machine language is made for some purpose(game,internet,video player,etc..) , we call it program.

Now, we are going to use programming language called JAVA to conversation with computer