1. Lecture 1
Introduction to Programming
Tariq Ali, Room No 21

2. Outline
 A computer is a useful tool for solving a great
variety of problems.
 To make a computer do anything (i.e. solve a
problem), we have to write a computer program.
 In a computer program we tell a computer, step
by step, exactly what want to do.

3. What is program
“A precise sequence of steps to
solve a particular problem”

4.  Following each step mechanically, to accomplish
the end goal.
 The sequence of steps to be performed in order
to solve a problem by the computer is known as
an algorithm.
 Flowchart is a graphical or symbolic
representation of an algorithm. It is the
diagrammatic representation of the step-by-step
solution to a given problem.

5. Concept of Languages
 Languages are used for
Communication between Users and
Computers.

6. Program Design Process
 Program Design consists of the steps a
programmer should do before they start coding
the program in a specific language. Proper
program design helps other programmers to
maintain the program in the future.

7. Problem Solving

8. Problem Solving is easy if you follow
these steps
Understan
d
the
problem

9. Step 1 – Understand the problem
 Read the problem carefully.
 Find the important information.
 Write down the numbers.
 Identify what the problem wants
you to solve.
 Ask if your answer is going to
be a larger or smaller number
compared to what you already

10. Step 1 - Understand the Problem
Read the problem carefully.
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?

11. Step 1 - Understand the Problem
Find the important information.
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?

12. Step 1 - Understand the Problem
Write down the numbers.
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?
Total = 31 1st week =14

13. Step 1 - Understand the Problem
Identify what the problem wants
you to solve.
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?
Total = 31 1st week =14
2nd week =

14. Step 1 - Understand the Problem
Ask if your answer is going to be a
larger or smaller number compared to
what you already know.
Total = 31 1st week =14
2nd week =
?
It will be smaller than the total but
may or may not be smaller than
the first week.

15. Problem Solving is easy if you follow
these steps
Decide
how
you’re
going to
solve the
problem

16. Step 2 - Decide how you’re going to
solve the problem
Choose a method
Use a graph Use
formulas
Write an equation Make a list
Find a pattern Work
backwards
Use reasoning Draw a picture
Make a table Act it out

17. Step 2 - Decide how you’re going to
solve the problem
Write your equation
Total = 31 1st week =14
2nd week =
Since I know both weeks total 31 I
?
write
14 + s = 31

18. Step 2 - Decide how you’re going to
solve the problem
Write your equation
Total = 31 1st week =14
2nd week =
I can use the inverse operation to
?
solve for s
14 + s = 31 31 – 14 = s

19. Problem Solving is easy if you follow
these steps
Solve
The
Problem

20. Step 3 - Solve the problem
Total = 31 1st week =14
2nd week =
? 312
1
–14
17

21. Problem Solving is easy if you follow
these steps
Look
Back &
Check

22. Step 4 - Look Back & Check
Reread the problem
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?
Total = 31 1st week =14

23. Step 4 - Look Back & Check
Substitute your new number
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second= 31
Total week?
1st week =14
2nd week = 17

24. Step 4 - Look Back & Check
Substitute your new number
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?
14 + 17 = 31

25. Step 4 - Look Back & Check
Did your new number work?
Luis earned 14 Accelerated
Reading points the first week
of November. At the end of
the following week he had a
total of 31 points. How many
points did he earn the
second week?
14 + 17 = 31 Yes!

26. Write an equation to solve this
problem.
Jaylynn had $84.75 in her
savings account. She made a
deposit. Her new balance was
$107.03. How much was her
deposit?
$84.75 + d = $107.03
Inverse operation
$107.03 – $84.75 = d

27. Write an equation to solve this
problem.
Anthony has twice as many
pokemon cards as Joshua. If
Anthony has 124 cards, how
many does Joshua have?
2 x d = 124 2d = 124
inverse operation d = 124/2

28. Write an equation to solve this
problem.
Vicki baked 90 cookies . If there
are 15 cookies in each batch.
How many batches did she
bake?
15 x b = 90 15b =90
inverse operation b = 90/15

29. Write an equation to solve this
problem.
Navneet has 3 times as many
CD’s as Arlene. If Navneet has
36 CD’s, how many does Arlene
have?
3 x c = 36 3c =
inverse operation c = 36/3
36

30. Write an equation to solve this
problem.
A square has a perimeter of 48
inches. What is the length of
each side of the square.
4 x s = 48 4s =
48 operation s = 48/4
inverse

31. Write an equation to solve this
problem.
One year the city ambulance
responded to emergencies on
293 days. How many days were
there no emergencies?
293 + d = 365
inverse operation d = 365 - 293

32. Credits
 Clipart from Broderbund ClickArt 125,000
Deluxe Image Pak
 Clipart from Corel Gallery by Corel Corp.

33. Program Design Phases
 Program Design Process Include:
 Problem Solving Phase
 Implementation Phase

34. Problem Solving Phase
 Problem solving is a skill which can be developed
by following a well organized approach.
 Programming is also a problem solving activity.
 Programmer use software development method
to solve problems.

35. Software development activities
 The following steps can be followed to solve any
kind of problem:
1. Problem Identification
2. Specify Requirements
3. Analyze Problem
4. Design algorithm and draw flowchart
5. Write the program (Coding)
6. Testing and Debug the program
7. Implement the program
8. Maintain and Update the program
9. Document the program

36. Problem Identification
 At this stage the problem being solved is
observed carefully.
 Major area of concern are identified.
 Irrelevant information is filter out.

37. Specify Requirements
 This stage demands to make clear the user’s
requirements so that a proper solution could be
suggested.
 Requirements are documented here.

38. Analyze the problem
 Problem is decomposed into sub-problems.
 This lead to simple solution
 The technique is known is top down design (also
called divide and conquer rule).
 To approach the right solution we may ask certain
questions:-
i. How many solutions are there to the given problem?
ii. Which one is the best solution?
iii. What are the input and output?
iv. How can the bigger problem be divided into sub
problems?

39. Design Algorithm and draw Flowchart
 Designing the algorithm requires to develop a
finite list of steps to solve a problem.
 Once algorithm has been designed it should be
verified through desk checking.
 Desk Checking is the process of carefully observing the
working of an algorithm, on the paper, for some test data.
 After designing the algorithm, the next step is to
draw a flowchart.
 Flowchart in fact, maps the algorithm to a pictorial
presentation which helps in understanding the
flow of control and data in algorithm.

40. Write the Program (Coding)
 Coding involves the conversion of an
algorithm to a program, written in any
programming language.
 The programmer must know the syntax of the
programming language chosen.
 The grammatical rules of a programming
language to write programs are referred to as
syntax of that programming language.

41. Test and Debug the program
 Testing requires evaluating the program to verify
that it works as desired.
 Debugging is the process of finding and removing
errors in the program.

42. Test and Debug the program
 There can be three types of errors:-
 Syntax Errors:-
 Occur when program violates one or more
grammatical rules of the programming language.
 Usually detected at compile time by the compiler.
 There can be many reasons such as typing wrong
commands or program statements.

43. Test and Debug the program
 Logical Errors:-
 Logical errors occur when program follow a wrong
logic.
 The translator (compiler or interpreter) does not
report any error message for a logical errors.
 Can be identified by just looking at the wrong output
of the program.

44. Test and Debug the program
 Runtime Errors:-
 A runtime error occurs when the program directs the
computer to perform an illegal operation such as
dividing a number by zero.
 When runtime error occur, the computer will stop
executing the program and may display a diagnostic
message that helps in locating the error.

45. Implement the Program (deployment)
 Once the program has been tested thoroughly, it
must be installed or put into operation at the site
where it will be used.

46. Maintain & Update the Program
 Program maintenance is ongoing process of
upgrading the program to accommodate new
hardware and software.
 Regular maintenance is essential to the
continued usefulness of a program.

47. Document the program
 Documentation is a detailed description of a
program’s algorithm, design, coding
method, testing and proper usage.
 A comprehensive documentation consists of the
following:
 A description of what the program is supposed to do.
 A description of the problem solution (the algorithm).
 A description of the program design including any aids used
(flowcharts, algorithms etc.).
 A description of the program’s testing process, including test
data used and result obtained.
 A description of all correctness modification and updates
made to the program.
 A user manual (user guide).

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