Saurabh Khatri Lecturer

Department of Computer TechnologyVIT, Pune

Unit 1: Introduction to Programming

Syllabus Unit 1: Introduction to Programming

Unit 2: Flow of Control and Functions

Unit 3: Arrays and Strings

Unit 4: Pointers and Structures

Unit 5: Recursive Functions – Sorting and Searching

Books to refer “Let us C”, Y. Kanetkar, Second Edition, BPB Publication. ISBN:

8176566217. “Programming In Ansi C” By E. Balagurusamy Tata McGraw-Hill

Education, 2008 “Programming language – ANSI C”, Brain W Kernighan and Dennis

Ritchie, Second edition ISBN 0-13-110370-9, Fundamentals of Computer System - Pradeep Sinha. For Unit 1

Assessment Total assessment = 100 15 – CT (7.5) on Unit 1+ HA (6*5 = 30 ------ 7.5) – Part B 20 – Mid Sem (Online test) MCQ – Unit 2,3 65 – End Sem (100 marks to be converted to 65)[Distribution of Marks Unit wise : 14+14+14+22+22+14]

What is a Computer?

4 Functions of a Computer Input : Any raw data given to Computer system Processing : Operations on Input according to set of

instructions. Output : Interpreting processed information to User Storage : Storing the results for future use.

Block Diagram of Computer

Operating System

Operating Systems System Software that controls the entire Computer System. Provides user with an interface to work with the Machine More convenient

Two way work of OS : Convenience + Resource management

Main functions Process mgmt Memory mgmt File mgmt Security

DOS OS that provides management of secondary storage devices Extension to the OS DOS was first used for IBM PCs using 32-bit Intel Processors

(x86). Microsoft developed the - Microsoft Disk Operating System

(MSDOS), MS windows 2007, XP are coming from it. Replaced by Windows OS completely Examples include DOS/360 and FreeDOS.

UNIX OS Unix is a multitasking, multi-user computer operating

system Developed in 1969 by a group of AT&T Bell Labs Contributors includes Ken Thompson, Dennis Ritchie, Brian

Kernighan and team Unix written in C language.

Levels of Programming Language Machine Language

Consists of combination of 0’s and 1’s that represent high and low electrical voltage. Unsuitable for programming, difficult to program. Machine dependent. Error prone. All programs are converted into machine language before they

can be executed.

Levels of Programming Language Assembly Language Similar to Machine level but replacing 0s and 1s with Names

and symbols Also known as Object code Uses symbolic codes to represent the machine operation code More readable Can be used to write instructions. Ex: ADD ------- 3E, etc Platform Dependent .obj extension

Levels of Programming Language High-Level Languages Programming languages that are easier to learn. Uses English like statements. Readable familiar notations Availability of program libraries Platform Independent. Hides the details of computer. Example C language (.c extension)

Execution of a Program

High Level source code(.c)

Middle level object

code(.obj)

Low level executable code(.exe)

Program Execution

Program Execution Compiler Assembler Linker Loader Interpreter(Video - )

ALGORITHMS AND FLOWCHARTS

A typical programming task can be divided into two phases: Problem solving phase produce an ordered sequence of steps that describe solution of

problem this sequence of steps is called an algorithm

Implementation phase implement the program in some programming language

Example 1 Example 1:Write an algorithm to determine a student’s final

grade and indicate whether it is passing or failing. Algorithm

Step 1: StartStep 2: Input M1,M2,M3,M4Step 3: GRADE (M1+M2+M3+M4)/4 Step 4: if (GRADE < 50) then

Print “FAIL”else

Print “PASS”endif

Step 5: Stop

Flowchart A graphical representation of the sequence of operations

in an information system or program. Different symbols are used to draw each type of

flowchart. A Flowchart shows logic of an algorithm emphasizes individual steps and their interconnections e.g. control flow from one action to the next

Flowchart Symbols Basic

Example

PRINT“PASS”

Step 1: Input M1,M2,M3,M4Step 2: GRADE (M1+M2+M3+M4)/4 Step 3: if (GRADE <50) then

Print “FAIL”else

Print “PASS”endif

START

InputM1,M2,M3,M4

GRADE(M1+M2+M3+M4)/4

ISGRADE<50

PRINT“FAIL”

STOP

YN

Example 2 Write an algorithm and draw a flowchart that will read the two sides of a rectangle and calculate its area.

Example 2

Algorithm Step 1: Input W,L Step 2: A L x W Step 3: Print A

START

InputW, L

A L x W

PrintA

STOP

Example 3 Write an algorithm and flowchart to print the factorial of a

no. N.

Revision – 15 Marks1. 4 functions of Computer? 2. Why RAM is also called Non Volatile. 3. Which is faster secondary or primary memory?4. Function of control unit?5. What is OS – example6. C is a _______________ level language.7. Machine code contains ______________ and has an extension ____________. 8. What is the function of Linker. 9. C is a Interpreted Language ? T or F. 10. Loader is part of ____________ and is used to __________________________. 11. For processing the executable file are brought to __________________ from

______________________. 12. Write an example of O/P and I/P device. 13. Interpretation process does not create any ___________________. That’s why it has a

drawback________________________. 14. Assembler function is to ________________________________________.15. is ____________________box