c programming language and data structure for dit students
TRANSCRIPT
C programming Language and
Data Structure
For DIT Students
Course Detail
Theory 100
Piratical 100
Total 200
Introduction to C Programming
Introduction
Books
“Turbo C Programming for PC”, Robert Lafore, SAMS
“Data Structure” ,Schaum’s Series
Language?
Source of Communication between two persons.– Example: Human –To- Human
OR Source of Communication between User
and Computer is called programming language.– Example: Human –To- Machine
Program
Set of instructions which perform any specific task is called program.
What is programming? Series of instructions to a computer to achieve a task
Instructions must be written in a way the computer can understand
Programming languages are used to write programs
Once the code (language) of a program has been written, it must be executed (run, started).
Some programming languages (like C, C++ or Java) require the code to be compiled (translated to binary) before it can be started.
History of C language
Year Language Developer1960
ALGOL(Algorithmic Language) Internal Committee
1967BCPL(Basic Combined Programming
Language)Martin Richards
1970 B Ken Thompson
1972 C Dennis Ritchie
What is C?
C A language written by Dennis
Ritchie in 1972 at AT&T Bell Labs USA. This was to be the language that UNIX was written in to become the first "portable" language.
In recent years C has been used as a general-purpose language because of its popularity withprogrammers.
AT&T-American Telephone and Telegraph UNIX-Uniplexed Information and Computing System or Service
Why C Still Useful?
C provides: Efficiency, high performance and high quality Provide functionality through rich set of function libraries Gateway for other professional languages like C C++ Java
C is used: System software, Compilers, Editors Graphics and Geometry Databases, operating systems, device drivers Also used in application programs
Software Development Method
Requirement Specification – Problem Definition
Analysis – Refine, Generalize the problem definition
Design – Develop Algorithm: (A formula or set of steps for solving a
particular problem)
Implementation – Write Code
Verification and Testing – Test and Debug the code
How do you write a program?
Decide what steps are needed to complete the task
Write the steps (Algorithm) in pseudo code (written in English) or as a flowchart (graphic symbols)
Translate into the programming language
Try out the program and “debug”.
Sample Pseudo code
Task: add two numbers Pseudo code (Algorithm) :
1. Start
2. Get two numbers
3. Add them (a + b)
4. Print the answer
5. End
What does a flowchart look like?
Pseudo code (Algorithm) :
1. Start
2. Get two numbers
3. Add them (A + B)
4. Print the answer
5. End
Start
Get 2 numbers
A+B
Print answer
End
START/END
INPUT/OUTPUT
PROCESS
DECISION
Flow Chart symbols
Integrated Development Environments
An integrated development environment (IDE) is a software package that makes it possible to edit, compile, link, execute, and debug a program without leaving the environment.
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Simple C Program
/* A first C Program*/
#include <stdio.h>
void main()
{ printf("Hello World");
}
Simple C Program
/* A first C Program*/
#include <stdio.h>
void main()
{ printf("Hello World");
}
Header File
Main Function
Opening bracket
Statement Part
Closing Bracket
Preprocessor directive
Simple C Program
Line 1: #include <stdio.h>
As part of compilation, the C compiler runs a program called the C preprocessor. The preprocessor is able to add and remove code from your source file.
In this case, the directive #include tells the preprocessor to include code from the file stdio.h.
This file contains declarations for functions that the program needs to use. A declaration for the printf function is in this file.
Simple C Program
Line 2: void main()
This statement declares the main function. A C program can contain many functions but must
always have one main function. A function is a self-contained module of code that can
finish some task. The "void" specifies the return type of main. In this case,
nothing is returned to the operating system.
Simple C Program
Line 3: {
This opening bracket denotes the start of the program.
Simple C Program
Line 4: printf("Hello World ");
Printf is a function from a standard C library that is used to print strings to the standard output, normally your screen.
The compiler links code from these standard libraries to the code you have written to produce the final executable.
If there were another printf in this program, its string would print on the next line.
Simple C Program
Line 5: } This closing bracket denotes the end of the program.
Comment Comment should be enclosed between /* */ It is used to increase the readability of the program. Any number of comments can be given at any place
in the program. Comment cannot be nested
example:
/* A first C Program*/
Steps in learning English language
Steps in learning C
AlphabetsDigitsSpecial-symbols
ConstantsVariablesKeywords
Instruction Program
Getting started with C
Alphabets Sentences ParagraphWords
The C character Set
• A character denotes any alphabet, digit or special symbol used to represent information.
Alphabets A,B, …. ,Y, Z a,b, ….. ,y, z
Digits 0,1,2,3,4,5,6,7,8,9
Special Symbols ~ ‘ ! @ # % ^ & * ( ) _ - + = | \ { } [ ] : ; “ ‘ < > , . ? /
Constants, Variable and keywords The alphabets, numbers and special symbol
when properly combined form constants, variables and keywords
A constant is a quantity that doesn’t change
A variable is a name given to the location in memory where the constant is stored
Example: 3x + y = 20 3 & 20 are constants, which cannot changex & y can vary or change hence are called variables
Keywords
• Keywords are the words whose meaning has already been explained to the C compiler
• Sometimes called reserved words.• They cannot be used as variable names.• There are only 32 keywords available in c
auto double if static dobreak else int struct gotocase enum long switch signedchar extern near typedef whileconst float register union defaultcontinue far return unsigned forshort void
Escape Sequence
Certain non printing characters can be expressed in terms of escape sequences
\n new line \t tab \a alert \\ backslash \” double quote \0 Null \b Backspace
Data Types
• C Supports several different types of data, each of which may be represented differently within the computers memory.
• Basic data types are listed below: Data Type Description Typical Memory
int integer quantity 2 bytes char single character 1 bytes float floating point number 4 bytes
Escape Sequences in C Certain non printing characters can be expressed in terms of
escape sequences
Character Escape Sequence
bell \a backspace \b horizontal tab \t vertical tab \v newline \n carriage return \r quotation mark (“) \” question mark(?) \? backslash (\) \\ null \0
Development with C
Four stages
Editing: Writing the source code by using some IDE or editor
Preprocessing or libraries: Already available routines
compiling: translates or converts source to object code for a
specific platform source code -> object code– linking: The object code of a program is linked with libraries
that are needed for execution of a program. The linker is used to link the program with libraries. It creates a file with '*.exe' extension.
Program Development
Source File
Program Object Code File
Executable File
Preprocessor
Modified Source Code in RAM
Compiler
Linker
Editor
Keywords
Sometimes called reserved words.
Are defined as a part of the C language.
Can not be used for anything else!
32 keywords in C
Examples:
– Int
– void
– while
– for