What are the basics of c?

In this language we can write our programs very easily.
After starting a c program first we can understand the steps which are given below⬇
1. Variable- variable is an entity whose value kept on changing throughout the program execution. We can easily change the value of any variable in whole program. It is very special case of the program. Hence it is not a rule that the value shall change. The value of variable can be same throughout the program execution.
Then we can discuss the defrences between constant and variable,
Here if we follow opposite rules of variable then we discuss about Constant it means that the value of constant might remain same throughout the program.
We can't change the value of constant in the program execution.

Let's take an example....

We defined the variable named v in a program. Let's say v=5.
After some time we can change the value of v to 7 or v to 9.
Now v=7 is getting change in the program. But we can't change the value of v if it defined as a constant.
2.Keyword-
The words whose meaning has already been defined in the c compiler is called
keyword.
The key word also called reserved words.
There are 32 keyword available in c.
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There are some keyword given below..
Int, float, char,auto, break, return, void, union, if, do, short, case etc.

I think you understand about keyword but the word compiler is new.
So we want to know about this word compiler is a device which converts users language into binary language.
Because we all know that computer reads or understand only binary language.