4.
C- Programming
4.1.
Introduction to C-Language Programming
Structured programming
Advantages
of structured programming
a)
Reduces complexity and easy to code.
b)
It takes less time to program and
easy to debug.
c)
Reuse of modules and flow of control
is clear.
C language
C Language is a high-level structured programming language which is used to
develop system software.
Dennis Ritchie at
Bell telephone laboratory developed C-language in early 1970s.
C is called middle
level language because it combines elements of high level language with some
features of assembler.
Data types used in C
Data
type are means to identify the type data and associated operation of handling
it.
Data types used in C language
a) char b) int c)
float d)
double e) void
155. Why
C is called a middle level language?
C is
called middle level language because it combines elements of high level
language with some features of assembler
Features of C language
a)
C
is a Structured Programming Language. which break down a program in several
small modules and makes the programmer easier to manage and debug the code.
b)
C
combines elements of a high level language with some features of assembler
which helps to manipulates memory address.
c)
C
is a case-sensitive programming language. It understands the capital alphabets
and small alphabets as different values.
d)
C
is many time faster and efficient than BASIC due to the variety of data type
and a list of powerful operators, programs written in C language.
Limitations of C language
a)
There is no runtime checking. It has
poor errors detection system.
b)
It
does not support object oriented programming.
c)
C
language has only 32 Keywords
d)
There is no strict type checking int
data type to float variables.
Application of C
Language
a) Operating
System
b) Language
Compilers/Interface
c) Assemblers
d) Text Editors
e) DBMS
f) Utilities etc.
C Token
C tokens are the
basic buildings blocks in C language which are constructed together to write a
C program.
Each and every
smallest individual unit in a C program are known as C tokens
C tokens are of
six types.
a) Keywords (eg:
int, while),
b) Identifiers
(eg: main, total),
c) Constants (eg:
10, 20),
d) Strings (eg:
“total”, “hello”),
e) Special symbols
(eg: (), {}),
f) Operators (eg:
+, /,-,*)
C keywords
(reserved word)
Keyword is a set
of special words which are already defined for some tasks.
C has only a set
of 32 keywords, which have their predefined meaning and cannot be used as a
variable name.
E.g. 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 Character set
Character Set is a
group of valid characters and symbols supported by a programming language.
Alphabets, Digits and Special characters.
Identifiers
Identifiers are
the names given to the entities such as variables, functions, arrays structures
and unions.
E.g. int price;
float total; Here, price and total are called identifiers.
Rules for naming
Identifiers:
i) The Identifier
must start with an alphabet or an under score (_).
ii) Identifier can
be made from the combination of alphabets, digits and under score.
iii) No any C
keyword can be used as an Identifier.
iv) Identifier
must be unique and can be used for a single purpose only.
Format Specifier
The format
specifier is used during input and output operation. It tells the compiler what
type of data is stored in a variable during the input and output operation such
as taking data from keyboard and display data on the screen. Some examples are
%c, %d, %f, etc.
|
Data Type |
Format Specifier |
|
short int |
%hd |
|
unsigned short
int |
%hu |
|
unsigned int |
%u |
|
int |
%d |
|
long int |
%ld |
|
unsigned long
int |
%lu |
|
char |
%c |
|
float |
%f |
|
double |
%lf |
C Header Files
stdio.h - Used for
standard input and output (I/O) operations. [printf( ), scanf( ), getchar( )]
conio.h - Contains declaration for console I/O
functions. [clrscr( ), exit( )]
math.h - D e c l a
r e s m a t h e m a t i c a l functions and macros. [pow(), squr(), cos(),
tan(), sin(), log() ]
string.h - Used
for manipulating strings. [strlen(), strcpy(), strcmp(), strcat(), strlwr(),
strupr(), strrev() ]
Escape Sequence
Escape Sequence is
a pair of character that is used with printf() function to display non-printing
character or a special character on the screen.
Some Examples of
Escape Sequence:
\n - new line
\t - tab
\b - backspace
\o - null
character
\? - question mark
\\ - slash
\' - single quote
\” - double quote
Format Identifier
We need to include
format identifier to tell the data type in the area of format string of
printf() function.
|
Variable Type |
Format
Identifier |
|
char |
%c |
|
int |
%d |
|
long int |
%ld |
|
float |
%f |
Variable
A variable is a
location in the memory of a computer which holds data in a program and its
value may change during the execution of program.
Constant
Constant
are the values that do not change during the execution of a program.
String Constant
String constant is a message to be displayed
along with the other values stored in variables. It is enclosed within double
quotation (" ").
Output Function in
C
Output function is
used to show the calculated result or output on the screen.
In C language,
printf() is one of the output function defined in header file.
printf() function
In C Language,
printf() function is used to print the valued on the screen.
It is defined in
header file. So, the header file must be added to use this function.
Input Function in
C
Input function is used to ask data for
processing.
In C language,
scanf() is one of the input function defined in header file.
scanf() Function
scanf() is one of
the most important functions of C Program.
This function is
also defined in the header file and used to ask value from keyboard.
getch() function
getch() function
is another input function of C language.
This function is
defined in the header file .
This function is
used to ask any one character from keyboard.
Arithmetic
Calculations in C Program
There are
basically four types of arithmetic operations:
i) Addition
ii) Subtraction
iii) Multiply
iv) Division
List of Arithmetic
Operators in C
+ (Plus) -
Addition
- (Minus) –
Subtraction
* (Asterisk) –
Multiplication
/ (Slash) –
Division
% (Percentage
Symbol) – Modulus Division
++ (Plus Plus) –
Increment Operator
- - ( M i n u s M
i n u s ) – Decrement Operator
Operator
Operators
are special symbols that are meant for specific tasks or operators.
The
different types of C operators are:- Arithmetic operators, Assignment
operators, Unary operators, Relational
operators, Logical operators and Conditional operators.
Arithmetic
operators are the operators that are used for manipulating arithmetic data and
performs arithmetic operation. The arithmetic operators are:- +,
- , * , / and
%
The
operator that operate on one operand variable or constant is called urinary
operator. E.g. ++, - -
C Expression
An expression
consists of at least one operand with one or more operators. It is a legal
combination of symbols that represents a value.
Logical
Calculation in C
The calculation
that is done based on one or more conditions is called logical calculations.
Several relational
or comparison operators are used to check the condition which gives True or
False as a calculated result.
Relational
Operators in C
Relational
Operator checks the relationship between two operands and returns either 1
(True) or 0 (False).
In C programming,
relational operators can be used to take decisions and provide condition in
looping statements.
List of Relational
Operators in C
= = Equal to
> Greater than
< Less than
!= Not equal to
>= Greater than
or equal to
<= Less than or
equal to
Control structures
in C
a) Sequence
structure (straight line paths)
The statements are
executed one after another sequentially from top to bottom without changing the
flow of program.
b) Selection
structure (one or many branches)
The control of the
program is transferred from one part of the program to another on the basis of
specified condition or without condition.
If statement and
switch statement are the examples of selection structure.
c) Loop structure
(repetition of a set of activities)
Looping is the
process of repeating the execution of a statement or a block of statements
guided by a condition. A loop is terminated when the given condition is
satisfied.
Looping statements
in C
C provides three
kinds of loops: i) while loop ii) do loop iii) for loop
Give the
name of any two header files used in C language
<stdio.h>
and <conio.h>
Name the
header/library file that handles mathematical functions in C Language.
-
<math.h>
What
will be the value of ‘y’ in given C expression, y=64%5?
The
value of y will be 4.
What will be the value of x in given c expression x=55 %
10?
The
value value of x will be 5.
How many
keywords are in C language?
There
are set of 32 keywords in C language.
What is
an operator in C language?
Operator
is a symbol that is used to perform mathematical operations.
Write the name of unary operators used in C-language
Increment
(++) and decrement (--).
Write
the name of two selection statement used in C language.
- if and
switch statement
Write
any two looping statements used in C language.
for and
while loop
1List
any two examples of format specifier (Conversion Character) used in C Language.
Any two
examples of format specifier (Conversion Character) used in C Language are %d
(int) and %f (float)
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