Friday, 28 August 2015

Learn C Language–Tutorial 2: Getting started with C

 Learn C Programming is a series of tutorials on c language. Follow my simple instructions and You also can become the C programmer.
In the first tutorial I have said how to run a C program. You can view the tutorial by clicking the link
In that tutorial I have said about What is a C language and the method of how to run the C language. But I have not yet told about the basic things in the C program.
To be tell this in detail consider an example that we learn English language since it is a global language for communication. We do not learn English in a single day, first we learn the alphabets and then we use the alphabets to combine the letters and form a word. Then we learn some grammar to create a sentence. Refer the diagram for clear understanding

  Like that in order to learn a C language there are some basic things we need to learn like alphabets, numbers, keywords, special symbols, constants, variables and how these are constructed and used in the C program.
Steps involved in learning C language
In this tutorial i am going to mainly concentrate on the first box

Alphabets – A,B……Z and a,b….z
Digits – 0,1,2,3,4,5,6,7,8,9
special symbols – ~!@#$%^&*()_+=-/?”’>.<,:;[]{}
The alphabets, numbers,and special symbols when properly combined form constants, variables and keywords.
Constants and Variables
A Variable is simple to describe let us assume that to perform a simple addition calculation manually for example
add 5 and 3
we simply write it in a paper as
So we need a space to write the numbers for calculation for manual calculations we use paper and pen.
So in case of computer calculation how do we do ???
So a storage is required in terms of storing the numbers for calculations. Thus we use alphabets to store the numbers.
we use lower case letters to store a number.
That alphabet is called as a variable and the number stored is called as constants.
In order to use a variable to store some values we need to say to the computer that i am going to use this particular letter to store a value this process is called as variable declaration.
Consider the above example
Add 5 and 3
Consider the below is the storage in computer
If i am going to use a for storing 5 and b for storing 3
and c for storing result
Thus the concept of variables and constants are clearly explained.
There are two types of constants
1.Primary Constants
2.Secondary Constants
Primary Constants includes
  • Integer Constants
  • Real Constants
  • Character Constants
Integer Constants
An Integer Constant must be at least of one digit, it can be a negative or positive the integer constant lies between the range –2147483648n to +2147483647.
ex: 1,2,3000,-250
Real Constant
These are also called as Floating point constants.
A real constant must have at least one digit, it must have a decimal point, default sign is positive but it could have both positive and negative.
ex: +445.566 , –56.45, 456.0
Character Constants
A character constant is a single alphabet written within a inverted commas.
ex: ‘A’ , ‘a’
Types of Variables
The Variable is different for different data types. Data Type is nothing but it is a type of the data that it is a integer or character or String or float.
A variable names are names given to the storage location in memory.
A variable name is any combination of 1 to 31 alphabets, digits,underscores.
The first letter of the variable must be an alphabet or underscore.
No commas or blanks are allowed, no special symbols other than underscore should not be used.
ex: mat_marks, m5_marks, emp_name
If you notice that mat_marks and m5_marks are marks that are numbers and emp_name is a collection of character so how the complier will differentiate between these .
Here the data type is used
The numbers are int types names are char types
decimal values are float types.
ex: int num, char name, float percntage.
Now we are in the final discussion of this tutorial that it is Keyword.
Keywords are the predefined words whose meaning is already explained to the C compiler.
The Keywords cannot be used as a variable names.
There are 32 keywords available in C

In our upcoming tutorials we can deeply see about the above keywords.
I hope this tutorial will thought you some tips in c.
Keep visiting my blog …
stay tuned for further tutorials…