C programming unit 01

In this session, you will learn to:
Identify the benefits and features of C language
Use the data types available in C language
Identify the structure of C functions
Use input-output functions
Use constructs
Objectives

Identifying the Benefits and Features of C Language
Ken Thompson developed a new language called B.
B language was interpreter-based, hence it was slow.
Dennis Ritchie modified B language and made it a
compiler-based language.
The modified compiler-based B language is named as C.

C language:
Possesses powerful low-level features of second generation
languages.
Provides loops and constructs available in third generation
languages.
Is very powerful and flexible.
C as a Second and Third Generation Language

C language:
Offers all essentials of structured programming.
Has functions that work along with other user-developed
functions and can be used as building blocks for advanced
functions.
Offers only a handful of functions, which form the core of the
language.
Has rest of the functions available in libraries. These functions
are developed using the core functions.
Block Structured Language - An Advantage for Modular
Programming

Features of the C Language
The features that make C a widely-used language are:
Pointers: Allows reference to a memory location by a name.
Memory Allocation: Allows static as well as dynamic memory
allocation.
Recursion: Is a process in which a functions calls itself.
Bit Manipulation: Allows manipulation of data in its lowest form
of storage.

Using the Data Types Available in C language
The types of data structures provided by C can be classified
under the following categories:
Fundamental data types
Derived data types

Fundamental Data Types
Fundamental Data Types:
Are the data types at the lowest level.
Are used for actual data representation in the memory.
Are the base for other data types.
Have machine dependent storage requirement.
Are of the following three types:
char
int
float

The storage requirement for fundamental data types can be
represented with the help of the following table.
Data Number of bytes on a
32-byte machine
Minimum Maximum
char 1 -128 127
int 4 -2^31 (2^31) - 1
float 4 6 digits of precision 6 digits of precision
Fundamental Data Types (Contd.)

Derived Data Types
Derived Data Types:
Are represented in memory as fundamental data type.
Some derived data types are:
short int
long int
double float

The storage requirement for derived data types can be
represented with the help of the following table.
Data Number of bytes
on a 32-byte
machine
Minimum Maximum
short int 2 -2^15 (2^15) - 1
long int 4 -2^31 (2^31) - 1
double float 8 12 digits of precision 6 digits of
precision
Derived Data Types (Contd.)

Defining Data
The syntax for defining data is:
[data type] [variable name],...;
Declaration is done in the beginning of a function.
Definition for various data types is shown in the following
table.
Data definition Data type Memory defined Size (bytes) Value assigned
char a, c; char a
c
1
1
-
-
char a = 'Z'; char a 1 Z
int count; int count 4 -
int a, count =10; int a
count
4
4
-
10
float fnum; float fnum 4 -
float fnum1,
fnum2 = 93.63;
float fnum1
fnum2
4
4
-
93.63

Practice: 1.1
Write the appropriate definitions for defining the following
variables:
1. num to store integers.
2. chr to store a character and assign the character Z to it.
3. num to store a number and assign the value 8.93 to it.
4. i, j to store integers and assign the value 0 to j.

Practice: 1.1 (Contd.)
Solution:
1. int num;
2. char chr=’Z’;
3. float num = 8.93;
4. int i, j=0;

Defining Strings:
Syntax:
char (variable) [(number of bytes)];
Here number of bytes is one more than the number of
characters to store.
To define a memory location of 10 bytes or to store 9 valid
characters, the string will be defined as follows:
char string [10];
Defining Data (Contd.)

Practice: 1.2
Write the appropriate definitions for defining the following
strings:
1. addrs to store 30 characters.
2. head to store 14 characters.

Practice: 1.2 (Contd.)
Solution:
1. char addrs[31];
2. char head[15];

Summary
In this session, you learned that:
C language was developed by Ken Thompson and Dennis
Ritchie.
C language combines the features of second and third
generation languages.
C language is a block structured language.
C language has various features that make it a widely-used
language. Some of the important features are:
Pointers
Memory Allocation
Recursion
Bit-manipulation

Summary (Contd.)
The types of data structures provided by C can be classified
under the following categories:
Fundamental data types: Include the data types, which are used
for actual data representation in the memory.
Derived data types: Are based on fundamental data types.
Fundamental data types:
char, int, and float
Some of the derived data types are:
short int, long int, and double float
Definition of memory for any data, both fundamental and
derived data types, is done in the following format:
[data type] [variable name],...;

Summary (Contd.)
In C language, the functions can be categorized in the
following categories:
Single-level functions
Multiple-level functions
For standard input-output operations, the C environment uses
stdin, stdout, and stderr as references for accessing the
devices.
There are two types of constructs in C language:
Conditional constructs
Loop constructs

Each Unit contains 40 to 60
slides in it. 

C programming unit 01

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