C programming language was developed in 1970s at Bell Laboratories by Dennis Ritchie. Programming languages can be classified as low-level languages and high-level languages. Low-level languages like machine language and assembly language interact directly with the computer's hardware. High-level languages like C use operators and code that is easier for humans to read and write but need to be compiled into low-level languages. The document then discusses various functions defined in the header file that perform operations like checking if a number is even, finding the prime factors of a number, calculating the length, sum and reverse of a number.

1. „C‟ Programming language
Language: - language is a medium of communication.
Communication: - It is two way process.
Programming: - It is a set by step execution Ex. Birthday party
Programming Language: - The language we need to interact with the computer is called
programming language.
„C‟ language was developed in 1970‟s at bell laboratories by Dennis Ritchie
 Computer is first made for doing large amount of calculation.
 Programme is set of instructions.
Programming language
1) High level
2)Low level
Low level language: - Low level languages are the machine level and assembly
language.
1) Machine language:-computers are understands only digital signals. Which are
binary digit o &1 the machine language consists of instructions that are in binary 0
or 1. Computer understanding machine level language
2) Assembly language: - It is the modified form of machine level language assembly
language is given in English like words such as , add, sub, etc
High level language:-Use of operators interacts of mnemonic code the solution of
mnemonic codes (they work on English language) because for them we need to use and learn
all these coded. Ex. Operators +,-,*, / etc
COBOL ==== Business Purpose
FORTON ==== Calculations Purpose
PASCAL====Science
Purpose........etc
 System independent- via OS
 These are like English language it is easy to understand the programme of high level
language.
 Every language has its own compiler or interpreter Ex. COBOL (business) basic Pascal
(calculation) etc.
 System deportment
 Which can interact with system directly

2.  In low level programming are made for machine. To make the computerized machine.
 We use coding in machines because its interacts with system directly.
Drawback:  These languages were for some specific task.
 Can use only predefined function and cannot modified it no use programmer not
bit programming (system programming)
Hence assembly language program must be translated into machine language. The
translator that is used for translating is called “assembler”
English==== (H.L.L) ========Compiler===== (L.L.L) ===== 0 & 1
148 languages are working at present time.
/* this program...*/: - The symbols /* and */ delimit a comment. Comments are ignored by the
compiler 1, and are used to provide useful information for Humans that will read the program.
Bit level Programming: Software: - A set of one or more programs designed to control the operation of a computer system. They
are general programs written to assist humans in the use of computer system and for making the
operation of the computer system more effective and efficient.
Software
System software
Application Software
1) System software: - Aaise software jo hardware ko chalane ke lia able banayein. Ex.
Drivers, keyboard, Mouse, Operating System
2) Application Software: - Application software for performing particular task. It is
requirement of user Ex. Windows‟s media player, M.S offices, tally, etc.
System software
Middle level language
Application software
Note: - C is a HLL with low level features that is why it is known as middle level
language.

3. ALGOL 60................................in 1960
CPL.........................................
BCPL...................................................
B (ken Thomson).....................
C.............................................. in 1972
12 years
C: - c is stable language because
develop Dennis Ritchie language at AT ans
T Bell Laboratory, USA
.h: - Extinction of header file.
Extinction, It is the identification of file. Ex- .mp3, .doc, .txt, etc
Function: -It is the groups of statement or it is the block
In C language 48 header files and 3200 function.
There are two typesFirst formatted function and second is unformatted function.
1) Stdio.h: - (standard input output header file)
Ex- printf (); scanf (); gets (); puts (); etc
Question: what is f?
Answer: -it is used f end of the function. And other unformatted function.
String: -sequence of the character “hello”.
Conio.h: - (console input/output)
Delimiters: - delimiters are used for syntactic meaning in C. These are as given follows.
Delimiters
:
Name
Colon
syntactic meaning
used for label
;
Semicolon
end of statement
()
Parentheses
Used in expression
[]
Square brackets
{}
statements
Curly Braces
#
directive
Hash
,
Comma
Used for array
Used for block of
Pre-processors
Variable delimiter
C Character Set: - The character that are used to form the words, numbers and expressions. The
character are classified as follows



Letters
Digits
Special Characters

4. Letters:
C language comprises the following set of letters to form a standard program. They are :
A to Z in Capital letters.
a to z in Small letters.
Special Characters:
C language contains the following special character in association with the letters and digits.
Symbol
Meaning
~
!
#
$
%
^
&
*
(
)
_
+
|
`
=
{
}
[
]
:
"
;
<
>
?
,
.
/
Tilde
Exclamation mark
Number sign
Dollar sign
Percent sign
Caret
Ampersand
Asterisk
Lest parenthesis
Right parenthesis
Underscore
Plus sign
Vertical bar
Backslash
Apostrophe
Minus sign
Equal to sign
Left brace
Right brace
Left bracket
Right bracket
Colon
Quotation mark
Semicolon
Opening angle bracket
Closing angle bracket
Question mark
Comma
Period
Slash

5. Function: - function is a group of statement or a block of code, which is executed step by step when it is
called.
Generally hm function ka use value return karne ke lia karte hai.
Kisi kaam ko baar baar repeat karne ke lia hm function ka use karte hai.
Main advantage yeh hai ki reuse means reusability bole toh reusable .
There are two types
1.Predefine
2.User define
1.Predefine: yeh programmer ke through banayi jati hai.
2.User define yeh user ke through but bina predefine function ke help ke bina user define nhi
banaya jaa skta hai Q ki statement ki code hmare bas kin hi hai……..
Way of writing of create function or way of coding
Syntax: likhane kaa tarika hm function ko create karne ke kia kaise likhenge
Syntax:< > (angular bracket)  that filled mandatory
[ ] ( optional bracket)according to wise(jararut ho toh lagao yaa mat lagao)
Syntax:
<return type><function name>([function parameter])
{
Body of statement
}
1:
<return type>
Jis type kaa data aap return karna chahte hai aap kar skte ho jaise..
Intfloatdouble etc….
*Agar aap kisi type kaa address return karna chahte hain toh pointer laga do.
Jaise ….int*float*double* etc
** Kisi bhi type kaa type kaa address return karana chahte hai toh toh void* lagalo.
Agar aap return nhi karna chahte ho toh void laga do.
Return type me data type ata ayega…by default agar aaap koi data type nhi lete hain toh wo int laga leta
hai .
2: <function name> jo variable pe rule hai same wahi 8 rule yaha bhi kareenge.
1.no space allow no use special char etc.
Parameter[];
Parameter me hm variable dete hain jise hm signature kahte hain
** jitney parameter ki variable declare kia ho calling ke time bi utne hi variable hone chahia.
Jaise…

6. Void show (int a,int b)
{
}
Show(10,x);
Void show(int a,int b,float c)
// show is the signature
{
}
Show(10,x,10.0);
Function hm four type ke create karte hain.
1- Without return type without parameter
Ex- void show() // called fuction
Printf(“welcome to the world of funtion”);
}
Void main(); calling funtion
{
Clrscr();
Show();
function calling
Getch();
}
2- Without return type with parameter
Ex- void prime(int x)
3- With return type without parameter
Ex- int show()
4- With return type with parameter
Ex- int add(int a,int b)
Hm function kaa ek program banate hai,
Void show()
{
Printf(“enter the would of funtion”);
}
Void display()
{
Show();
}
Void main()
{
Clrscr();
Display();
Getch();

7. }
Jab bhi aap function banaye wo calling function ke upper hi banaye Q ki hmra compilre waha tak nhi
pahuch pata hain wo toh uska proto type matching check karta hain.
Wo matching -2 dhundhega toh chalega agar aap calling function ke niche banana chahte hain toh
upper aap ko uska proto type declear(likhana hoga) karna hoga.
Ex.
Void show();
Void main()
{
Clrscr();
Show();
Getch();
}
Void show()
{
Printf(“hellow”);
}
**pahle sare proto type likh lo phir coading karo okay
Need of parameter:
1----user se value lena
2—fixed value
3— function ke ander function
Note--- aalag -2 funtion me same name ke variable ho skte hain.
Ex—
Void add1(int a,int b)
{
Printf(“%d”,a+b);
}
Void main()
{
Int a,b;
Clrscr();
add1(10,20);
Add1(pow(2.3),sqrt(1));
Pirintf(“%d%d”,a,b);
Add1(a,b)
Getch();
}
Return statement can return only one value at a time…………..

8. Ex-1
Int add (int a,int b)
{
Return a+b;
}
Ex-2
Int add (int a,int b)
{
Return a+b; // yaha se program teminate ho gayega
Return a-b;
}
Note: hme saare function ke return type banana chahia jinse koi ek value aati ho
Toh waha return karao
Call by value call by rreference:::: jab aap fuction ko call karenge as a parameter koi vale pass
karenge toh waha call by value hoga..
100% me se 95% call by value se hi function ki calling hoti hai.
Call by reference:--------------------------------------------------------------------------------------------
_ _ _ __________________________________________________________________________ ______
Header file: groups of function.
Ex. <My.h>
Codind……..
int iseven(int n)
Functin of cheak even or not
{
if(n%2==0)
return 1;
else
return 0;
}
int isleap(int n)
{
if((n%4==0 && n%100!=0)||(n%400==0))
return 1;
else
return 0;
}

9. int isprime(int n)
{
int i;
for(i=2;i<=n/2;i++)
{
if(n%i==0)return 0;
}
return 1;
}
long length(long n)
{
int count=0;
while(n>0)//123>0,12>0,1>0,0>0
{
count++;//count=0+1=1+1=2+1=3
n=n/10;//123/10=12/10=1/10=0
}
return count;//3
}
long sum(long n)
{
//123
long s=0;
while(n>0)
{
s=s+n%10;
n=n/10;
}
return s;
}
long rev(long n)
{
//123
long s=0;
while(n>0)
{
s=s*10+n%10;
n=n/10;
}
return s;
}
ispal(long n)
{
long s=0;
long x;

10. x=n;
while(n>0)
{
s=s*10+n%10;
n=n/10;
}
if(s==x)return 1;
else
return 0;
}
isarm(long n)
{
long s=0,x;
x=n;
while(n>0)
{
s=s+(n%10)*(n%10)*(n%10);
n=n/10;
}
if(s==x)return 1;
else
return 0;
}
int fact(int n)
{
int i,x=1;
for(i=1;i<=n;i++)
{
x=x*i;
}
return x;
}