c programming unit 01
TRANSCRIPT
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 ac
11
--
char a = 'Z'; char a 1 Z
int count; int count 4 -
int a, count =10; int acount
44
-10
float fnum; float fnum 4 -
float fnum1, fnum2 = 93.63;
float fnum1fnum2
44
-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.
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.
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