1. Software Life Cycle What Requirements Gathering, Problem definition
How
Analysis and Design (Programming techniques)
Do it
Coding
Test
Testing
Use
Implementation and Maintenance

2. Coding and Testing Write Program Compile Program Run and Test Program
Submit Program
Success
Correct Errors
Errors

3. How to develop a program
Identify the steps and execution sequence.
Every program consist of mainly three parts:
Input, Processing and Output
Example: Add two numbers
Steps
Read/Input two numbers
Add these two numbers
Display/Output the result of addition
Algorithm : Steps written in English language.
Program : Algorithm written in a specific high level language.

4. Algorithm
An Algorithm is a solution to a problem that is independent of any programming language.
An Algorithm is
a finite sequence of steps
each step shall be clearly stated and understandable
for each input, it shall terminate in finite time with output
How we solve the problem with Computer?

5. Program and Programming
A set of instruction written in a programming language that a computer can execute so that the machine acts in a predetermined way.
Program solves a problem
Before writing a program:
Have a thorough understanding of the problem
Carefully plan an approach for solving it.
Programming:
The Process of providing instructions to the computer that tells the processor what to do.

6. Algorithms & Programs
An Algorithm is a solution to a problem that is independent of any programming language While
A program is an algorithm expressed using a specific set of instructions from any programming language.

7. Algorithm Example Maximum of two numbers Steps:
Read/input two numbers
Compare two numbers
Print the Greater number
Average of three numbers
Read/input three numbers
Add three numbers
divide the sum by 3.
Print the result of divison

8. Pseudocode This is a common notation for writing algorithms.
Mixture of English language statement and a programming language( like C) code.
It is an intermediate step in writing a program.
Not actually executed on computers.
Standard mathematical notations like exponents,square-root symbols etc. are allowed in pseudocode.

9. Rules for pseudo code
The beginning and end of a pseudo code is marked with keywords START and STOP.
Every variable should be initialized in the beginning only using INITAILZE
Values from user should be accepted using keyword READ, and should be display using WRITE.
All “alphanumeric” values should be enclosed in single or double quotes.
All the nested loops are: for-do-done, while-do-done
All the control structures are: if-then-else-fi, switch-case.

10. Examples Pseudo code to find out the sum of all
odd numbers in the range 1 to 10.
START
INITIALIZE a[10], sum=0,i
for i=1 to 10 do
Read a[i];
if (condition) then
Calculate sum=sum+a[i];
done
Write sum;
STOP

11. Examples Pseudo code to find out the maximum number from 20
given numbers.
START
INITIALIZE a[20],max,i;
for i=1 to 20 do
Read a[i];
done
max=a[1];
for i=2 to 20 do
if a[i]>max then
Assign max=a[i];
Write max;
STOP

12. Practice Example Write an algorithm for the given problem:
10 students of a class appears for a test in three
subjects. Each test is out of 100 marks. The percentage
of each student has to be calculated and depending on
the percentage calculated, grades are given below:
Percentage
Grade
> =80 A
60-79 B
<=59 C

13. Flowchart Graphical representation of an algorithm Components:
Arrows/lines :Flow of control
Parallelogram: Indicates input and output operations
Rectangle symbol (action symbol): Indicates any type of action/computational step
Oval symbol:Indicates the beginning or end of a program or a section of code
Diamond: Decision

14. Flowchart Notations
Arrows
Diamond
Parallelogram
Oval
Rectangle

16. Example: Add two Numbers
READ
A,B
C=A+B
PRINT C
START
STOP

17. Draw both flow chart and pseudo code
You are required to calculate area of circle and rectangle.
Accept from user the figure and then accordingly calculate and display.

18. Pseudo code label 1: START INITIALIZE FIG, area=0; READ FIG ;
IF FIG = “circle”
CALL CIR_ROUTINE ;
ELSE
IF FIG=“rectangle”
CALL RECT_ROUTINE ;
GOTO label 1;
ENDIF
WRITE “ area of figure”, area;
STOP
label 1:

19. CIR_ROUTINE
INITIALIZE radius=0;
READ radius;
CALCULATE area = 3.14 * radius * radius;
RETURN to Calling procedure
RECT_ROUTINE
INITIALIZE length=0, width=0;
READ length,width;
CALCULATE area = length*width;
RETURN to Calling procedure

20. Flow Chart READ FIG START FIG? other rectangle READ LENGTH & WIDTH
circle
READ
RADIUS
AREA=LENGTH * WIDTH
PRINT
AREA
AREA=3.14*RADIUS * RADIUS
STOP

21. Problems GCD of three numbers Calculate 2n
Roots of equation ax2+bx+c=0
Largest of N numbers
Generate the fibonacci series