Lesson 01
Programming with C
Pijushkanti Panigrahi
What is C ?
• The C is a programming Language, developed by
Dennis Ritchie for creating system applications
that directly interact with the hardware devices
such as drivers, kernels, etc.
• C programming is considered as the base for
other
programming
languages,
that
is
why
it
is
other
programming
languages,
that
is
why
it
is
known as mother language.
• C is famous for its Compactness.
• C language is case sensitive.
2
Features
It can be defined by the following ways:
Mother language
System programming language
Procedure-oriented programming
language
language
Structured programming language
Mid-level programming language
3
1) C as a mother language ?
• C language is considered as the mother language of all the
modern programming languages because most of the
compilers, JVMs, Kernels, etc. are written in C language,
and most of the programming languages follow C syntax, for
example, C++, Java, C#, etc.
• It provides the core concepts like the array, strings,
functions
,
file
handling
,
etc
.
that
are
being
used
in
many
functions
,
file
handling
,
etc
.
that
are
being
used
in
many
languages like C++, Java, C#, etc.
4
2) C as a system programming language
• A system programming language is used to
create system software.
• C language is a system programming
language because it can be used to do
low-level programming (for example
driver and kernel).
• It is generally used to create hardware
devices, OS, drivers, kernels, etc. For
example, Linux kernel is written in C.
5
3) C as a procedural language
• A procedure is known as a function, method,
routine, subroutine, etc. A procedural
language specifies a series of steps for
the program to solve the problem.
•
A
procedural
language
breaks
the
program
•
A
procedural
language
breaks
the
program
into functions, data structures, etc.
• C is a procedural language. In C, variables
and function prototypes must be declared
before being used.
6
4) C as a structured programming language
• A structured programming language is a
subset of the procedural
language. Structure means to break a
program
into
parts
or
blocks
so
that
it
may
program
into
parts
or
blocks
so
that
it
may
be easy to understand.
• In the C language, we break the program into
parts using functions. It makes the program
easier to understand and modify.
7
5) C as a mid-level programming language
• C is considered as a middle-level language
because it supports the feature of both low-level
and high-level languages. C language program is
converted into assembly code, it supports pointer
arithmetic (low-level), but it is machine independent
(a feature of high-level).
• A Low-level language is specific to one machine,
i.e., machine dependent. It is machine dependent,
fast to run. But it is not easy to understand.
• A High-Level language is machine independent. It
is easy to understand.
8
Variables in C
• A variable is a name of the memory
location. It is used to store data. Its value
can be changed, and it can be reused
many times.
•
It
is
a
way
to
represent
memory
location
•
It
is
a
way
to
represent
memory
location
through symbol so that it can be easily
identified.
• Let's see the syntax to declare a variable:
data_type variable_list;
9
Data Types in C
• A data type specifies the type of data that a variable can
store such as integer, floating, character, etc.
• There are the following data types in C language.
Types Data Types
Basic Data Type
int
, char, float, double
Basic Data Type
int
, char, float, double
Derived Data Type array, pointer, structure, union
Enumeration Data Type enum
Void Data Type void
10
• The example of use of data types is given below:
int a; float b; char c;
• Here, a, b, c are variables. The int, float, char are
the data types. We can also provide values while
declaring the variables as given below:
declaring the variables as given below:
int a=10,b=20;//declaring 2 variable of integer type
float f=20.8;
char c='A';
11
Rules for defining variables
• A variable can have alphabets, digits, and
underscore.
• A variable name must start with an alphabet,
and underscore only. It can't start with a digit.
• No whitespace is allowed within the variable
name
.
name
.
• A variable name must not be any reserved word
or keyword, e.g. int, float, etc.
• Valid variable names:
int a; int _ab; int a30;
• Invalid variable names:
int 2; int a b; int long;
12
C-language program
a general structure
1 Calling header files #include <stdio.h>
2 Main function main()
3 Starting brace {
4
Variable(s) declaration
int
a;
4
Variable(s) declaration
int
a;
5 Executable statement(s) printf () etc
6 Closing brace }
13
/* To Print a message */
#include <stdio.h>
main()
{
printf
("Hello
C
Programming
\
n");
printf
("Hello
C
Programming
\
n");
}
14
Output
Hello C Programming
printf() function
• The printf() function is used for output. It
prints the given statement to the console,
defined in stdio.h (header file).. The syntax of
printf
()
function
is
given
below
:
printf
()
function
is
given
below
:
printf("format string", argument_list);
• The format string can be
%d for integer, %f for floating point number,
%c for single character, %s for a string etc.
15
scanf() function
• The scanf() function is used for input ,
defined in stdio.h (header file). It reads the
input data from the console.
scanf
("format
string", &
argument_list
);
scanf
("format
string", &
argument_list
);
• The format string can be
%d for integer, %f for floating point number,
%c for single character, %s for a string etc.
16
/* Program to print cube of given number */
#include<stdio.h>
main()
{
int number, cube;
printf("enter a number:");
scanf
("%
d",&number
);
scanf
("%
d",&number
);
cube=number*number*number;
printf(“ cube of number is:%d “ cube,);
}
------
Output
enter a number:5 cube of number is:125
17
• The scanf("%d",&number) statement reads
integer number from the console and stores the
given value in number variable.
• The printf("cube of number is : %d",
cube) statement prints the cube of number on
the console.
18
/* Program to print sum of 2 integer numbers */
#include<stdio.h>
main()
{
int x=0,y=0,result;
printf("enter first number:");
scanf("%d",&x);
printf
("enter
second
number:");
printf
("enter
second
number:");
scanf("%d",&y);
result=x+y;
printf("sum of 2 numbers:%d ",result);
}
Output
enter first number:19 enter second number:11 sum of 2 numbers:30
19
If-else Statement
• The if-else statement in C is used to perform the
operations based on some specific condition. The
operations specified in if block are executed if and only if
the given condition is true.
•
There
are
the
following
variants
of
if
statement
in
C
•
There
are
the
following
variants
of
if
statement
in
C
language.
if statement
if-else statement
If-else-if ladder
Nested if
20
if Statement
The if statement is used to check some given
condition and perform some operations depending
upon the correctness of that condition. It is mostly
used in the scenario where we need to perform the
different operations for the different conditions. The
syntax
of
the
if
statement
is
given
below
.
syntax
of
the
if
statement
is
given
below
.
if(expression) if (a>b)
{ {
executable statement(s); printf (“a is large”);
} }
21
#include<stdio.h>
main()
{
int a, b;
printf("enter a:");
scanf("%d",&a);
printf("enter b:");
scanf("%d",&b);
if(a>b)
{
{
printf(“a is large”);
}
}
-------
Output
• enter a:14 enter b: 12 a is large
• enter a:19 enter b: 25
22
if-else Statement
• The if-else statement is used to perform two
operations for a single condition. The if-else
statement is an extension to the if statement using
which, we can perform two different operations, i.e.,
one is for the correctness of that condition, and the
other
is
for
the
incorrectness
of
the
condition
.
The
other
is
for
the
incorrectness
of
the
condition
.
The
syntax of the if-else statement is given below.
if(expression)
{ executable statement 1;
}
else
{ executable statement 2;
}
23
#include<stdio.h>
main()
{ int a, b;
printf("enter a:"); scanf("%d",&a);
printf("enter b:"); scanf("%d",&b);
if(a>b)
{
printf(“a is large”);
}
else
else
{
printf(“b is large”);
}
}
-------------
Output enter a:14 enter b: 12 a is large
enter a:19 enter b: 25 b is large
24
#include <stdio.h>
main()
{ int age;
printf("Enter your age?"); scanf("%d",&age);
if(age>=18)
{ printf("You are eligible to vote..."); }
else
else
{ printf(“You are not eligible to vote..."); }
}
-----
Output
• Enter your age?28 You are eligible to vote...
• Enter your age?13 You are not eligible to vote....
25
if-else-if ladder Statement
The if-else-if statement is an extension to the if-else
statement. It is used in the scenario where there
are multiple cases to be performed for different
conditions. In if-else-if ladder statement, if a
condition is true then the statements defined in the
if
block
will
be
executed,
otherwise
if
some
other
if
block
will
be
executed,
otherwise
if
some
other
condition is true then the statements defined in the
else-if block will be executed, at the last if none of
the condition is true then the statements defined in
the else block will be executed.
26
Syntax of if-else-if statement
if(condition1)
{
executable statements 1;
}
else if(condition2)
{
executable statements 2;
}
}
else if(condition3)
{
executable statements 3 ;
}
...
else
{
executable statements last;
}
27
Program to prepare the result of the student
#include <stdio.h>
main()
{ int marks;
printf("Enter your marks?"); scanf("%d",&marks);
if(marks >=600)
{ printf("Congrats ! you are place in the FIRST CLASS"); }
else if (marks >=500)
{ printf("You are placed in the SECOND CLASS"); }
else
if
(marks
>=
400
)
else
if
(marks
>=
400
)
{ printf("You are placed in the THIRD CLASS"); }
else
{ printf("Sorry you FAILED"); }
}
Output
Enter your marks?31 Sorry You FAILED
Enter your marks?478 You are placed in THIRD CLASS
Enter your marks?545 You are placed in SECOND CLASS
Enter your marks?726 Congrats ! you are place in the FIRST CLASS
28
