Number Crunching in c | Numbers Programs in c language | Top 15 Useful Examples of Number Programs In c

 Basics c programming  language

OVERVIEW OF C PROGRAMMING

C language is one of the most popular computer languages today because it is a structured, high level, machine independent language. It allows software developers to develop programs without worrying about the hardware platforms where they will be implemented. C is called a high level, compiler language. The aim of any high level computer language is to provide an easy and natural way of giving a programme of instructions to a computer.

C is one of a large number of high level languages which can be used for general purpose programming, i.e., anything from writing small programs for personal amusement to writing complex applications. It is unusual in several ways. Before C, high level languages were criticized by machine code programmers because they shielded the user from the working details of the computer. The C language has been equipped with features that allow programs to be organized in an easy and logical way. This is vitally important for writing lengthy programs because complex problems are only manageable with a clear organization and program structure.

C allows meaningful variable names and meaningful names to be used in programs without any loss of efficiency and it gives a complete freedom of style, it has a set of very flexible loop constructions and neat ways of making decisions. These provide an excellent basis for controlling the flow of programs. Another feature of C is the way it can express ideas concisely. The richness of a language shapes what it can talk about. C gives us the apparatus to build neat and compact programs. C tries to make the best of a computer by linking as closely as possible to the local environment.

The increasing popularity of C is probably due to its many desirable qualities. It is a robust language whose rich set of built-in functions and operators can be used to write any complex program. The C compiler combines the capabilities of an assembly language with the features of a high-level language and therefore it is well suited for writing both system software and business packages. Programs written in C are efficient and fast. This is due to its variety of data types and powerful operators. C is highly portable. This means that C programs written for one computer can be run on another with little or no modification. Another feature of C is its ability to extend itself.

Introduction c programming language

C is a remarkable language. Designed originally by Dennis Ritchie, working at AT&T Bell Laboratories in New Jersey, it has increased in use until now it may well be one of the most widely- written computer languages in the world. C is a structured language. It allows variety of programs in small modules. It is easy for debugging, testing, and maintenance if a language is a structured one.

Structure of c program

Include header file section 

Global declaration 

section main()

{

Declaration part Executable part

}

User-defined functions

{

Statements

}

Include Header File Sections

C program depends upon some header files for function definition that are used in program. Each header file by default is extended with .h. The header file should be included using   # include directive as given here.

Global Descretion

This sectiondeclares some variablesthat are used in more than one function. These variables are known as global variables. This section must be declared outside of all the functions.

Function Main

Every program written in C language must contain main () function. The function main() is a startingpoint of every C program.The execution of the programalways begins with the function main ().

Discretion Part

The declaration part declares the entire variables that are used in executable part. The initialisations of variables are also done in this section. Initialisation means providing initial value to the variables.

Executable Part

This part containsthe statements following the declaration of the variables. This part conatins a set of statements or a single statement. These statements are enclosed between the braces.

User Defined Functions

The functions defined by the user are called user-defined functions. These functions are generally defined after the main () function.

Steps for Executing a C program

1.    Creation of program

Programs should be written in C editor.The file name does not necessarily includeextension C. The default extension is C.

2.    Compilation of a program

The source programstatements should be translated into object programswhich is suitable for execution by the computer. The translation is done after correcting each statement. If there is no error, compilation proceeds and translated program are stored in another file with the same file name with extension “.obj”.

3.    Execution of the program

After the compilation the executable object code will be loaded in the computers main memory and the program is executed.

CHARACTER SET

Letters	Digits	White Spaces
Capital A to Z	All decimal digits 0 to 9	Blank space
Small a to z		Horizontal tab
		Vertical tab
		New line
		Form feed

 Special Characters

,	Comma	&	Ampersand
.	dot	^	Caret
;	Semicolon	*	Asterisk
:	Colon	-	Minus
'	Apostrophe	+	Plus

"	Quotation mark	<	Less than
!	Exclamation mark	>	Greater than
|	Vertical bar	()	Parenthesis left/right
/	Slash	[ ]	Bracket left/right
\	Back slash	{}	Braces left/right
~	Tilde	%	Percent
_	Underscore	#	Number sign or Hash
$	Dollar	=	Equal to
?	Question mark	@	At the rate

Delimiters

Delimiters	Use
: Colon	Useful for label
; Semicolon	Terminates the statement
( ) Parenthesis	Used in expression and function
[ ] Square Bracket	Used for array declaration
{ } Curly Brace	Scope of the statement
# hash	Preprocessor directive
, Comma	Variable separator

    

C KEYWORDS

Auto	Double	Int	Struct
Break	Else	Long	Switch
Case	Enum	Register	Typedef
Char	Extern	Return	Union
Const	Float	Short	Unsigned
Continue	For	Signed	Void
Default	Goto	Sizeof	Volatile
Do	If	Static	while

Identifiers in c

    Identifiers are names of variables, functions, and arrays. They are user-defined names, consisting sequence of letters and digits, with the letter as the first character.

Constant 

Values do not change during the execution of the Program 

Types:

1. Numerical constants

Integer constants

These are the sequence of numbers from 0 to 9 without decimal points or fractional part or any other symbols. It requires minimum two bytes and maximum four bytes.

Eg: 10,20, + 30, – 14

Real constants

It is also known as floating point constants. Eg: 2.5, 5.342

2. Character constants:

Single character constants

A character constant is a single character. Characters are also represented with a single digit or a single special symbol or white space enclosed within a pair of single quote marks

Eg: 'a', '8', " "

String constants

String constants are sequence of characters enclosed within double quote marks.

Eg: “Hello”, “india”, “444”

VARIABLES in c Programming

It is a data name used for storing a data value. Its value may be changed during the program execution. The value of variables keeps on changing during the execution of a program.

DATA TYPES in c Programming

Data type	Size (Bytes)	Range	Format Specifiers
Char	1	– 128 to 127	%c
Unsigned char	1	0 to 255	%

Short or int	2	– 32,768 to 32, 767	%i or %d
Unsigned int	2	0 to 655355	%u
Float	4	3.4e – 38 to +3.4e +38	%f or %g
Long	4	= 2147483648 to 2147483647	%ld
Unsigned long	4	0 to 4294967295	%lu
Double	8	1.7e – 308 to 1.7e+308	%lf
Long double	10	3.4e – 4932 to 1.1e+4932	%lf

OPERATORS in c Programming

It indicates an operation to be performed on data that yields value.

Types

Type of Operator	Symbolic representation
Arithmetic operators	+, -, *, /, %
Relational operators	>, <, ==, >=, <=, !=
Logical operators	&&, ||, !=
Increment and decrement operator	++ and --
Assignment operator	=
Bitwise operator	&, |, ^, >>, <<, ~
Comma operator	,
Conditional operator	?:

Input AND Output

Reading data from input devices and displaying the results on the screen are the two main tasks of any program.

formatted Functions in c

The formatted input/output functions read and write all types of values

          Input                        Output

          Scanf()                     printf()

unformatted Functions in c

The unformatted input/output functions only work with the charcter data type

    Input                    Output

    getch()                           putch() 

    getche()                        putchar()

    getchar()                         put() 

    gets()

It checks the given condition and then executesits sub-block. The decision statement decides the statement to be executed after the success or failure of a given condition.DECISION STATEMENTS

Types:

1.    If statement

2.    If-else statement

3.    Nested if-else statement

4.    Break statement

5.    Continue statement

6.    Goto statement

7.    Switch() statement

8.    Nested switch ()case

9.    Switch() case and Nestedif

 

Statement	Syntax
If statement	if(condition) Statement;
If-else statement	If (condition)
	{
	Statement 1;
	Statement 2;
	}
	else
	{
	Statement 3;
	Statement 4;
	}
Nested if-else statement	If (condition) {

	Statement 1; Statement 2; } Else if (condition) { Statement 3; Statement 4; } Else { Statement 5; Statement 6; }
Break statement	Break;
Continue statement	Continue;
Goto statement	goto label;
Switch() statement	Switch (variable or expression) { Case constant A: Statement; Break; Case constant B: Statement; Break; Default: Statement;

LOOP CONTROL STATENENTS

Loop is a block of statements which are repeatedly executed for certain number of times.

Types

1.    For loop

2.    Nested for loops

3.    While loop

4.    do while loop

5.    do-while statement with while loop

Statement	Syntax
For loop	For(initialize counter; test condition; re-evaluation parameter) { Statement; Statement; }
Nested for loop	for(initialize counter; test condition; re-evaluation parameter) { Statement; Statement; for(initialize counter; test condition; re-evaluation parameter) Statement; Statement; } }
While loop	While (test condition) { Body of the loop }
Do while loop	do { Statement; } While(condition);
Do-while with while loop	Do while(condition) { Statement; } While (condition

 ARRAYS IN C Programming 

TypesIt is a collection of similar data types in which each

 element is located in separate memory locations.

1.    One dimensional array

2.    Two dimensional arrays

3.    Three or multi dimensional arrays

Operations

1.    Insertion

2.    Deletion

3.    Searching

4.    Sorting

5.    Merging

 

STRINGS In C Programming

Character arrays are called strings. Group of characters, digits,

symbols enclosed within quotation marks are called as strings.

string standard functionss in c 

Functions	Description
Strlen()	Determines the length of a string
Strcpy()	Copies astring from source to destination
Strncpy()	Copies charcters of a string to another string upto the specified length
Stricmp()	Compares characters of two strings
Strcmp()	Compares characters of two strings upto the specified length
Strncmp()	Compares characters of two strings upto the specified length
Strnicmp()	Compares characters of two strings upto the specified length
Strlwr()	Converts uppercase characters of a string to lower case
Strupr()	Converts lowercase characters of a string to upper case
Strdup()	Duplicates a string
Strchr()	Determines the first occurrence of a given character in a string
Strrchr()	Determines the last occurrence of a given character in a string
Strstr()	Determines the first occurrence of a given string in another string
Strcat()	Appends source string to destination string
Strrev()	Reverses all characters of a string
Strset()	Sets all characters of a string with a given argument or symbol
Strspn()	Finds up to what length two strings are identical
Strpbrk()	Searches the first occurrence of the character in a given string and then displays the string starting from that charcter

Function in C Programing

It is a self-contained block or a sub program of one or more statements that performs a special task.

Function_name (argument/parameter) Argument declaration;
        {                

    Local variable declaration; Statement1;
              Statement 2; Return (value);
        } 

CaII by vaIue

In this type, value of actual arguments is passed to the formal arguments and the operation is done on the formal arguments. Any change made in the formal argument does not effect the actual arguments because formal arguments are photo copies of actual arguments.

 

CaII by Reference

In this type, instead of passing values, addresses are passed. Function operates on address rather than values. Here the formal arguments are pointers to the actual argument.

Recursion

A function is called repetitively by itself.