C programing Tutorial

Mahira Banu
C PROGRAMMING TUTORIAL

C Programming Tutorial
Contents:
Introduction
a) History and Usages
b) Keywords
c) Identifiers
d) Variables and Constants
e) Programming Data Types
f) Input and Output
g) Programming Operators
Decision and Loops
a) If…If else and Nested If else
b) C Programming Loops
c) Break and Continue
d) Switch…..case Statement
e) go to function
C Functions
a) User Defined
b) Function Recursion
c) Storage class
Arrays
a) One Dimensional Array
b) Multi dimensional Array
Pointers
a) Pointers and Function
String
Structure and Union
a) Union
Advance Functions in C
a.) Enumeration
b.) Pre-processor
c.) Library Function

Chapter 1
Introduction
a.) History
C is a general purpose, structured programming language. It was
developed by Dennis Ritchie in 1970 in BELL Lab.
C Programming is widely used in the Programming world for to
develop all the advanced applications. This tutorial will use you to learn all the
basic things in the C Programming.
Advantages of C:
 Flexible
 Highly portable
 Easily extended by the user
 Faster and Efficient
 Include number of Built-In-function
Disadvantages of C:
 No runtime checking
 It is very executable to fixed bugs
Application of C:
 Unix completely developed by C
 Many desktop application developed by C
 Used to solve mathematical functions
 It is used to implement different OS.
Getting Started with C:
For clear understanding we have to run all the basic concepts, In order
to run programs we need compiler, compiler will change the source code to
object code and create executable files. For practical uses we install the basic
compiler Turbo C/ Advanced compiler Codelite.
Character Set:
Character set are the set of alphabets, numbers and some special
characters which is valid in C.

Alphabets:
Upper Case: A to Z
Lower Case: a to z
Digits:
0 to 9
Special characters:
Here some of the special characters used in C
> < $ ,
# ^ ” “
} { ( )
b.) Keyword:
Keyword is the reserved words used in programming. Each
keyword has fixed meaning and it cannot be changed by any users.
Ex: int money;
Here int is a keyword.
Keyword is a case-sensitive and all keyword must be in lower case.
Keywords in C Language
auto double int struct
break else long switch
case enum register typedef
char extern return union
continue for signed void
do if static while
default goto sizeof volatile
const float short unsigned

c.) Identifiers:
Identifiers are name given to C entities such as structures, keywords
or functions etc… Identifiers are unique name given to the C entities which is
used to identify during the execution.
Ex: int money;
Here money is an identifier. Identifier can be in Upper or Lower
case. It can be start with digits or “_”.
d.) Variables and constants:
Variables:
Variables are used to store memory location in system memory,
each variable have unique identifiers.
Ex: int num;
“num” is a variable for integer type.
Variable didn’t contain case sensitive, it may be start with underscore or digits.
Constants:
Constants are the term which cannot be changed during the execution of the
program. It may be classified into following types:
Character Constant:
Character constant are the constant which used in single quotation
around characters. For example: ‘a’, ‘I’, ‘m’, ‘F’.
Floating Point constant:
It may be numerical form that maybe fractional or exponential
form.
Ex: -0.012
1.23 etc…
Integer Constant:
Integers constant are the numeric constants without any floating
point/exponential constant or character constant. It classified into 3 types:
o Octal digits: 0,1,2,3,4,5,6,7
o Decimal Digits: 0,1,2,3,4,5,6,7,8,9
o Hexadecimal digits: 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H

Escape Sequence
Sometimes it is necessary to use newline, tab etc… so we have to use
“/” which is known as Escape sequence.
Escape Sequences
Escape Sequences Character
b Backspace
f Form feed
n Newline
r Return
t Horizontal tab
v Vertical tab
Backslash
' Single quotation mark
" Double quotation mark
? Question mark
0 Null character
String Constant:
Which are enclosed in double quote mark. For example
“good”.
Enumeration Constant:
Keyword enum is used to declare enumeration. For example
enum color{yellow,white,green}
here the variable name is yellow,white,green are the enumeration constant
which having values 0,1,2 respectively.
e.) Programming Data types
Data types in C are classified into 2 types:
1. Fundamental data types
2. Derived Data Types
Syntax for Data types: Data type variable name;

Classifications of Fundamental Data types
Integer Type: Keyword int is used for declaring with integer types
Floating Types: Keyword float and double are used for declaring the floating
types
Character Types: keyword char is used for declaring the variables of character
type.
Classifications of Derived Data types
 Arrays
 Structure
 Enumeration
 Pointers
Qualifiers: It is used to alter the meaning of base data types to yield a new data
type.
f.) Input/output:
The C Program input and output functions are printf() and scanf()
Printf() it’s used to provide output to the users
Scanf() it’s used to taken input from the users.
Examples for I/O function
#include<stdio.h>
Void main();
{
int c;
printf(“enter the number c”);
scanf(“%d”,&c);
printf(“number=%d,c”);
return 0;
}
Here printf() is used to display the output .

Scanf() is ask the value from the user ‘&’ denotes that the address of the C and
value stored in the number.
Stdio represent standard input output function which is the library function
#include is used to paste the code from the header when it is required.
g.) Programming Operators:
Operators are a symbol which operates on a value or variable. For Example:
+ is an operator which is used for a addition.
Operators in C programming
 Arithmetic operators(+,-,%,*)
 Increment and Decrement operators(a++,++a,a--,--a)
 Assignment operators(+=,a+=b is equal to a=a+b)
 Relational operators(==,<=,>=)
 Logical operators(&&,||)
 Conditional operators (?,: it’s used to making decision)
 Bitwise operators(&,| etc)

Chapter-2
Decision and loops
a.) If, If…else, Nested If…else….
This Statement is used to execute the programming by one
time decision i.e. execute one code and ignore one code.
If Statement
It executes the statement if the test expression is true.
Syntax:
if (test expression)
{
// statement to be executed when the test expression is true
}
If..else Statement
This statement is used when the programmer is want to execute one
statement if the test expression is true or executes other expression if the test
expression is false.
Syntax:

if (test expression)
{
Statement to be execute when expression is true;
}
else
{
Statement to be executed when it is false;
}
Nested if else statement
This statement is used when the programmers need more than one
expression.
The nested statement is work by step by step if first statement is true it never
enter t the 2nd
statement when it is wrong it will go to the next expression. This
will used by programmers when they need to check more than one expression.
Syntax:
if(test expression)
{
execute if expression is true; }

else if( test expression 1)
{
execute when expression 0 is false and 1 is true;
}
else if (test expression 2)
{
execute when expression 0 and 1 are false and 2 is true);
}
.
.
.
else
{execute the statement when all the above are false;
}
b.) C Programming Loops
Loops are used when the programmer wants to execute the same block
repeatedly for number of times. Loop function executes the certain block of
code until the code becomes false.
Types of Loops:
1. for Loop
2. while Loop
3. do…while Loop
for Loop
for loop execute the program block until the given statement is false.
Syntax:
for(initialization; expression; update statement)
{
Body of the code ;}

The Initialization process run only at initial stage of the
programming then it checks the expression if the expression is false loop is
terminated. It is true it executes the code of the body and then executes the
update statement. This process repeats until expression becomes false.

Example Program: Find out the sum of n Natural Numbers, when n is
entered by the users.
#include<stdio.h>
#include<conio.h>
int main()
{
int n,c,s=0;
printf("enter the value of n");
scanf("%d",&n);
for(c=1;c<=n;c++)
{
s=s+c;
}
printf("s=%d",s);
getch();
return 0;
}
Output
Enter the value of n=9
S=45

While Loop
It checks while expression is true of false. If the expression is true it
executes the body of the loop after the execution it checks the body again this
process continues until it becomes false.
Syntax:
while (test expression)
{
Body of the loop; }
Example: Find the factorial of the number
#include<stdio.h>
int main()
{
int factorial,number;
printf(“enter a number n”)
scanf(“%d”,&number);
factorial=1;
while(number>0)
{ factorial=factorial*number;
--factorial;
}

printf( factorial=%d”, factorial);
return 0; }
do…while loop
The only difference between the while and do while is it executes the
statement and then check the test expression.
Syntax:
do
{code to be execute; }
while(test expression);
Write a C program to add the numbers until the user enter the zero
#include<stdio.h>
int main()
{
int num,sum=0;
do
{ printf(“enter a number n”);
scanf(“%d”,&num);
sum=sum+num;
}
while(num!=0);

printf (“%d”,sum);
return 0;}
Summary
for loop while loop do..while loop
Initialization,
It is usually counter
variable, statement that
will be executed every
iteration of the loop,
until the counter variable
increment or decrement
It checks the condition
first, if condition is false
it never enter into the
loop.
It executes the
statement before checks
the condition at least one
iteration takes place
when the condition is
false
c.) Break and Continue
The two statements break and continue is used to skip or terminate the
some programming blocks without checking it.
Break statement
It is used to terminate the loop if the statement is true.
Syntax:
break;
Example: write a C program to find the average value of numbers, terminate
the program if the input is negative display the average value and end the
program
#include<stdio.h>
int main()

{
int n,i;
float average,num,sum;
printf(“maximum numbers of inputs”);
scanf(“%d”,&n);
for(i=1;i<=n;++i)
{ printf(“enter the n %d”,i);
scanf(“%d”,&n);
if(num<0)
break;
sum=num+sum;}
average=sum/(i-1);
printf(“Average=%.2f”,average);
return 0;
}
Continue Statement
To skip some statement in the function continue statement is used
Syntax;
continue;

Example: Write a C program to find the product of 4 numbers
#include<stdio.h>
int main()
{ int i,num,product;
for(i=1,product=1;i<=4;++i)
{ printf(“enter the num %d”,i);
scanf(“%d”,&num);
if(num==0)
continue;
product*=num;}
printf(“product=%d”,product);
return 0; }
Break Continue
It can appear in loop and switch
statements.
It can appear only in loop statement.
It terminates the switch or loop
statement when break is encountered.
It does not cause the termination,
when continue encountered it executes
all iteration in the loops
d.) switch…..case Statement
Decision making are used to select the particular block or code with many
other alternative codes. Instead of switch case we can use nested if else but it is
more complicated while compare with switch case.
Syntax:
switch (n) {
case constant 1:
A code to be executed if n is equal to constant 1;
break;
case constant 2:

A code to be executed if n is equal to constant 2;
break;
.
.
.
default:
codes to be executed if n is not equal to any constants;
}
Example Program: Write a program to select the arithmetic operator and two
operands and perform the corresponding operations
#include<stdio.h>
int main()
{
char o;
float n1,n2;

printf(“select an operator + or – or * or n);
scanf(“%c”,&o);
printf(“enter the two operands:”);
scanf(“%f%f”,&n1,&n2);
switch(o)
{
case +:
printf(“%.1f+%.1f=%.1f”,num1,num2,num1+num2);
break;
case -:
printf(“%.1f-%.1f=%.1f”,num1,num2,num1-num2);
case *:
printf(“%.1f*%.1f=%.1f”,num1,num2,num1*num2);
case :
printf(“%.1f %.1f=%.1f”,num1,num2,num1num2);
default:
printf(‘operator Error”);
break;
}
return 0; }
e.) go to function
This statement is used to altering the normal sequence of program by
transferring control to some other parts.
Syntax:
goto label;
…………….
…………….

label;
statement;
we are not using goto statement because it’s make more complex and
considered as a harmful construct. goto statement is replaced by the use of break
and continue statement.

Chapter 3
C Functions
A function is a segment which is used to perform the specified task. A
C program has at least one main() function, without main there is no C
programs.
Types of C Functions
Library Functions
User defined functions
Library Functions
It is a built in function in C programming
Example:
main() --- Every programs start with main function
print() --- used to display the output
scanf() --- used to enter the input
a.) User Defined Function
C allows the programmer to define the function according to their
requirements. For example, a programmer wants to find the factorial and check
whether it is prime number or not in the same program, we can use the 2
functions in the same program.
Working of User defined:
#include<stdio.h>
void function_name()
{……………………
………………………}
int main()
{ ………………………..
………………………….

Function name();
……………………
……………………. }
As we mentioned earlier C program is starts with main function when
the program reaches to the function name it jumps to the void function name
after execution of the void function it return to the function name and executes
it.
Advantages:
Easily maintain and debug, large no of codes easily divided in to small
segments and decompose the work load.
Example:
#include<stdio.h>
int add(int a,int b); //Function declaration(prototype)
int main()
{int num1,num2,sum;
printf(“enter the numbers to add”);
scanf(“%d %d”,&num1,num2);
sum=add(num1,num2); //function call
printf(“sum=%d”,sum);
return 0;
}
int add(int a,int b);
{
int add;
add=a+b;
return add;}

Function Declaration (prototype)
Every function has to declare before they used, these type of declaration
are also called function prototype. It gives compiler information about name,
function, type of argument that has to pass.
Syntax of Prototype
return-type fun-name ( type(1) argument(1)…………….type(n) argument(n));
From the above example
int add(int a,int b); this is function prototype
fun-name  add
return type  int
Function call:
Control of the program transferred to the user defined when the function
is called.
Syntax:
function_name(arg 1,arg2);
Function Definition:
It contains specific codes to perform specific task. It is the first line of function
declaration.
Syntax:
function name(arg(1),arg(2))
b.) Function Recursion:
The function that calls itself without any other external functions is known
as recursion.
Example:
#include<stdio.h>
int sum(int n);
int main()
{ int num,add;

printf(“enter a positive integer”);
scanf(“%d”,&n);
add=sum(n);
printf(“sum=%d”,add);
}
int sum(int n)
{
if(n==0)
return n;
else
return n+sum(n-1);}
Advantage:
 It is more elegant and requires few variables which make program clean
 It replaced the complex nesting code function.
Disadvantage:
 It is hard to write the recursion.
 Hard to debug.
c.) C Programming Storage:
Every variable has two properties:
 Type
 Storage
Type refers to the function whether it is integer or floating or character
Storage refers how long it stays. It is classifies into 4 types:
 Auto
 External
 Static
 Register

auto: Variable declared by the inside of the function by default. It access by the
local variables only.
external: It can be accessed by the any function. It is called as global variables
and it declared outside in the function.
static: The value of static variable persists until the end of the program.
register: Register variable are similar like auto and used in global variable.

Chapter-4
Arrays
Main use of array is to handle similar type of data’s. For example, if the
company wants to save 100 employees details. By using simple code form, the
programmer has to be creating the data for 100 employees individually, but by
using arrays we can easily replace it.
An Array is a sequence of data types for homogeneous type.
Arrays are two types
1. One Dimensional Array
2. Multi dimensional array
a.)One Dimensional Array:
Declaration of One Dimensional Array:
declaration_type array_name[array_size];
Example: int age[5];
Array Element:
Size of array defines the number of elements used in the array. Each
element can be accessed by the user by their usage.
int age[5];
Age[0] Age[1] Age[2] Age[3] Age[4]
Every array element can be start by 0;
Example:
#include<stdio.h>
void main()
{
int marks[10],i,n,sum=0;
printf(“enter the number of students:”);
scanf(“%d”,&n);
for(i=0;i<n;i++)

{ printf(“enter the number of students%d:”,i+1);
scanf(“%d”,&marks[i]);
sum=sum+marks[i];}
printf(“sum=%d”,sum);
return 0; }
b.) Multi Dimensional Array:
C Program allows programmers to create array of arrays in the
program.
Ex:
float a[2][6];
Here, an array of two dimensions, this is example of multi-dimensional array.
Initialization of Array:
a[2][4]={{1,2,0,0} ,{3,4,5,6}};

Chapter-5
Pointer
Pointers are the important feature it’s different the C and
C++ from java and other languages. Pointers are used to access the memory and
manipulate the address.
Reference Operator (&):
& denotes address in the memory
Lets explain in the program
#include<stdio.h>
int main()
{ int var=5;
printf(“value=%d”,var);
printf(“address=%d”,&var);
return 0;}
Output:
Value=5
Address=2567891
From the above code we can know clearly var is a name given to that location
and 5 is stored in the 2567891 location.
Reference Variable (*):
It is used to hold the memory address i.e is variable that holds address is
Reference variable
Arrays Pointers
Array is a single, pre-allocated and
continues element
Pointer is a place in a memory which is
used to store the another place or
function
It can’t be resized It can be resized

It can be initialized It can’t be initialized
a.) Pointers and Functions
When the Argument is passed using pointer address of the memory
location is passed instead of value.
Example:
#include<stdio.h>
void swap(int *a,int *b);
int main()
{ int n1=5,n2-10;
swap(&n1,&n2);
printf(“n1=%d n”,n1);
printf(“n2=%d’,n2);
return 0; }
void swap(int *a, int *b)
{ int temp;
temp=*n1;
*n1=*n2; *n2=temp; }
The address of n1 and n2 are passed to the memory location of pointer a and b,
So the value of the memory location changed the value in memory location also
changed, clearly if the *a and *b are changed it will reflected in n1 & n2
This is known as call by reference.

Chapter-6
String
Array of character is string.
Declaration of String:
String is declared like array the difference is string is denoted as char only
char S[5];
S[0] S[1] S[2] S[3] S[4]
Declaration by using pointer
char *p;
Initialization of string:
char c[]="abcd";
char[5]= "abcd";
char[]={‘a’, ‘b’,‘c’,‘d’,‘0’};
Example: How to read string from terminal
#include<stdio.h>
#include<string.h>
int main()
{char name[20];
printf(“enter name:”);
scanf(“%s”,name);
printf(“your name is %s:”,name);
return 0;}
output:
Enter name: Swan Tech
Your name is: Swan

Here the compiler will give the first name only because there is white
space
String Handling Functions
We can use strings for various application like finding length etc.. but
programmer can use the library function string.h in the program
We can manipulate the string function manually so we use the handling
functions.
Function Explanation
strlen() Length of the string
strcpy() Copy the string
strcat() Joins two string
strcmp() Compare two strings
gets() and puts()
we can use this gets and puts condition to take input string and display
the output string
Example:
#include<stdio.h>
#include<string.h>
int main()
{ char name[30];
printf(“enter the name”);
gets(name);
printf(“The name enter is:”);
puts(name);
return 0;}
Here gets and puts are likely scanf() and printf()

Chapter-7
Structure and Union
Structure:
Structure is the collection variable that is used to store the different variables
under a single name. If you want to store the different details of the students like
register number, marks, details etc
We are using structure for the better approach.
Definition:
Keyword struct is used for denote the function.
Syntax:
struct_structure name
{ datatype 1;
datatype 2;
.
.
datatype n;}
Union
Union is similar to the structure, it derived from the structure and we sued union
keyword to denote it in the code
The main difference is All members can be accessed the structure but only the
members in the union can access the code

Structure Union
Using keyword struct for denote Using keyword union for denote
One or more members can initialize
the function
Only one member can initialize
It allocates memory equal to the sum
of the memory allocated to its each
individual members
It allocates one block memory which is
enough to stored all the data
Each member have their own space Only one memory for all users

Chapter-8
Advance Function in c
a.) Enumeration
Enumeration is user defined data type consist of integral constant
and each integral constant have a keyword enum to defined the enumeration
type.
enum type_name{ value 1,value 2…….value n};
By default value 1=1 and value 2=1 but the user can changed the default values.
Example of Enumerated:
#include<stdio.h>
enum week{Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday};
int main()
{ enum week today;
Today=Wednesday;
printf=(“%d day”,total+1);
return 0;}
Output:
Today=4
b.) Pre-processor
In C language the line which is beginning with # symbol is
known as Pre-processor. It is substitution tool and it instruct compiler to do the
specific function before the compilation of the program.
Example:
#include  To insert particular header
#define  Substitute a particular macro

c.) Library Function
It is inbuilt function of C programming which is written with their
respective header files.
For Example: if you want to run printf() you need to include stdio.h in the
header file.

C programing Tutorial

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