Introduction to C Language Beginner’s Guide

Introduction to C Language Beginner’s Guide

 

 

 

 

 

In this tutorial article of introduction to C Language Beginner’s guide, we will discuss in detail basics and introduction to C Language. We will cover the introduction to C Language in soft and simple manner for our learners which are beginners in C Language and had just entered in the C Language learning.

 

What is C Language

 

C Language is a high level programming language used for the communication of the human with computer. And we have to learn C language for the better understanding of other programming languages especially object oriented programming like C ++.

 

History of C Language

C language the procedural programming language was first used by Dennis Ritche, an American programmer in 1972, at Americans Telephone and Telegraphs (AT&T’s), Bell laboratories.

 

Importance of C Language

• C language is the most important language and it is in fact, the first advanced programming language for general purposes. Following are some primary importance of  C Language.
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• Ø  C language is a small language, so it is easily understandable by operating system, where as other languages like C++,C# and Java are complex and big and operating system feels the difficulties while understanding them.
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• Ø  Secondly these programming languages like C++,C# and Java are object oriented languages and are difficult to learn from start to end without having any grip of C language.
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• Ø  Major parts of all the operating systems like Windows, Linux, Unix are written in C language.
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• Ø  Gaming platforms are also developed using the C Language.
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Constants Variables and Keywords of C Language

To learn programming language like C is just same as learning the ordinary language like English. If you want to learn English language you will probably start with alphabets, then convert them in the words, transform the words in sentences and then structured the sentences to build a paragraph.

                                                            

 

 

 

 

 

 

 

 

 

 

 

Same practice is here in C language, you have to first learn the alphabets of C language which are

Alphabets, Digits and Special Symbols

You will then combine these alphabets, digits and special symbols to form the words of C language which are

 Constants, Variables and Keywords

These words must be joined in some logical order to gain the C language sentence which is

Instructions/Statements

Finally you have to convert these instructions/statements to programs.

 

Now we are going to explore the each component of programming language in detail.

Alphabets, Digits and Special Symbols

We have all the alphabets capitalized or upper case and lower case or small letters.

In Digits, all the digits form 0 to 10 are included.

In Special symbols, all the symbols such as !,@,#,$ e.t.c are included.

 

 

 

 

 

 

 

 

 

Constants

The data stored in a variable or memory location is called as constant. In general, the value which doesn’t change is constant. In programming the data or value stored in variables or memory locations computer is called as constant.

One and the only thing to be noted about constant is that constant always stores in the variables.

 

Types of Constants in C language

Basically in C language we deal with the two types of constants.

 

Primary Constant includes the integer, real and character constants

Secondary Constant includes the array, pointers, structure, enum etc.

 

 

 

                                           Rules for Integer Constant

• 1.     At least one digit is necessary.
• 2.     There is no decimal point between digits.
• 3.     Comma or blanks around digits is not allowed.
• 4.     It may be positive or negative.
• 5.     The range of integer constant is between -2147483648 to +2147483647.
• 6.     Default sign will be positive.
• For example: +99, -34, -2, +34, 3 are all integer constants.

 

                          Rules for Real Constant

 

• 1.     Must have at least one digit.
• 2.     There must be decimal point between digits.
• 3.     Dash or comma is prohibited.
• 4.     Value may be positive or negative, whereas default sign is positive.
• For example: +9.9, -3.4, -2.0, +34.0, 3.0 are all real constants.

 

Exponential Case

 

Exponential form is usually used in real constants, when either the value is too large
or too small, but exponential form never restricts us to form real constants.
The part before E or e is called as mantissa and after part is exponent.
For Example: 0.0014 can be written as 1.4*10^-3 in normal form and 1.4e^-3   in exponential form.

 

 

 

                          Rules for Exponential Case

 

1.      The mantissa and exponent are separated by E or e.

2.      Mantissa must be positive or negative, default sign is positive.

3.      Exponential must have at least one digit.

4.      Exponent may be positive or negative, default sign will be positive.

5.      Exponential form must be in between -3.4e³⁸ to 3.4e³⁸  .

 

For example: -2.1e-10, 7.7e16,  -9.67e-19, 4.1E are all exponential case real constants.

 

 

                          Rules for Character Constant

1.      Character constant may be the single alphabet, single digit, of single special symbol enclosed with in a single inverted comma.

2.      The inverted comma both have the direction to left.

 

For example: ‘e’, ‘6’, ‘%’ are all exponential case real constants.

 

 

Variables

A variable is simply that store the constants. The variable can also be defined as entity which holds multiple values or which whose values changes.

In programming the name given to the particular memory location that holds some data or value is called as variable.

A particular type of variable can hold only particular type of data, As integer type variable will hold the integer type data. Real type variable will hold the real type data only and character type variable must hold character type data.

The rules for constructing particular integer, real or character constant are different but for creating the integer, real or character variable are same.

 

                          Rules for Variables creation

 

1.     You can use the alphabets, digits and underscore in combination or individually up to 31 or 247 characters depending on compilers.

2.     Always start the name of variable with _ or alphabets, digit is not allowed.

3.     Special symbols except _ are prohibited.

4.     No comma or blank is allowed.

 

For example: Pe_ple, in_detail, _23hsd, etc are variables name

 

 

                          Possibilities in Variables names

There are four possibilities in constructing variable names. You can use any possibility to name a variable.

1.      Only Alphabets

2.      Alphabets and Underscores

3.      Alphabets and digits

4.      Alphabets, digits and underscore

 

Keywords in C Language

Keywords are predefined words for the library of compiler or in broader sense computer whose meaning is already known to the computer.

There are too many keywords in different object oriented programming languages but C Language has only 32 keywords. These are

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                                We can’t use the keywords as variable names because if we do so it is to assign the new value to keywords which results in error. So it is safe to use the meaningful names of variables instead of keywords.

 

Variables Declaration in C Language

Assigning data type to a variable is called as the variable declaration. The point raised was that rules for creating the variable name for all the primary and secondary data types are same, so how C compiler differentiate between such variables names. That’s why the assigning of data type in the declaration of variable is mandatory so compiler can distinguish the variable name from its data type.

For example: int age; float temp, char name etc.

 

 

Variables Initialization in C Language

Assigning the value to a variable is called as variable initialization.

A variable can be initialized at the same time when it is declared. As

int age=16;

Or, A variable can be initialized in separate statement after the declaration. As

int marks;

marks=300;

 

Comments in C Language

Like all the other programming languages C language also has the facility of comments in code. These comments are just used to explain the purpose of program or the purpose of particular statement.

The text inside the comments is unknown to compiler and hence compiler will not execute the code in comments and simply ignore this text.

Types of comments

There are two types of comments in the C Language.

Single Line Comment

Single line comment uses the // in start of line and then comment is written after these slashes in single line. As

//This is a single line comment.

Multi Line Comment

Single line comment uses the /* in start of comment and */ at the end of comment, either comment is of one line or it spread over the multiple lines. As

/*Hello!.*/

/*Hello!.

This is a multi line comment */

 

OK with this knowledge in hand we can directly write the program in C language but we will not do so, we will first understand the basic structure of program in C Language.

Learn Basic Structure of Program in C language

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