1. CS110D: Programming Language I
Computer Science department
Lecture 1: Introduction to computers & problem solving

2. Lecture Contents Course Info. Problem Solving Techniques Examples
Pseudocode
Algorithm
Flow charts
Examples
Elements of a Computer system.
Evolution of programming languages
The code Life Cycle
dr. Amal Khalifa,Fall14

3. Course info Books and references Course plan
Assessment methods and grading
Labs and practical assignments
Practical exam

4. Books and references
[1] JavaTM Programming: From Problem Analysis to Program Design (Introduction to Programming) 5th Edition
Programming-Problem-Analysis- Introduction/dp/ X
[2] Deitel P.J., Deitel H.M. - Java. How to Program, 9th Edition
481/Java%20How%20to%20Program%209t h%20Edition.pdf
[1]
[2]

5. How Computers Solve Problems
Create a solution (called an Algorithm) which manipulates Data into Information
Computers use Algorithms to solve problems, and change data into information
Computers can only perform one simple step at a time
Dr. Amal Khalifa, 2014

6. Algorithms Example: Accelerating in a car
Algorithm: A step-by-step problem-solving process in which a solution is arrived at in a finite amount of time
Example: Accelerating in a car
Move right foot to gas pedal
Apply pressure to gas pedal with right foot
If speed is too high, apply less pressure.
If speed is too low, apply more pressure.
Dr. Amal Khalifa, 2014

7. Problem Solving Approach
Problem-solving process involves the following steps:
1. Analyze the problem and outline the problem and its solution requirements.
2. Design an algorithm to solve the problem.
3. Implement the algorithm in a programming language, such as Java.
4. Verify that the algorithm works.
5. Maintain the program by using and improving it, and modifying it if the problem domain changes.
Dr. Amal Khalifa, 2014

8. Expressing the Algorithms
A “Standard” way of describing an algorithm must exist if we expect our solution to be understood by others easily
There are standards in programming:
PSEUDOCODE
FLOWCHARTS
Dr. Amal Khalifa, 2014

9. Pseudo Code “Pseudo” means “pretend” or “false”
Pseudo Code is pretend or false computer code; uses generic English-like terms
Pseudo Code is not as standardized as flowcharts, and does not facilitate the breaking down of problems as well as a flowchart does
Dr. Amal Khalifa, 2014

10. Example
Write an algorithm to find the area and the perimeter of a rectangle
dr. Amal Khalifa,Fall14

11. Pseudo Code Example
design an algorithm to find the perimeter and area of a rectangle
Dr. Amal Khalifa, 2014

12. That’s all for Today!! Text book [1] chapter 1 (pages 13-16)
Dr. Amal Khalifa, 2014

13. Flowcharts
Graphical representations of algorithms or a tool to translate algorithm
A Flowchart uses easy-to-understand symbols to represent actions on data and the flow of data
Flowcharts aid in breaking down a problem into simple steps
Dr. Amal Khalifa, 2014

14. Flowchart Symbols
Dr. Amal Khalifa, 2014

15. flowcharting
Dr. Amal Khalifa, 2014

16. Example
Example 1: Write an algorithm and draw a flowchart to convert the length in feet to centimeter.
hint: I feet = 30 cm
Dr. Amal Khalifa, 2014

17. Pseudocode Input the length in feet (Lft)
Calculate the length in cm (Lcm) by multiplying LFT with 30
Print length in cm (LCM)
Dr. Amal Khalifa, 2014

18. Algorithm Step 1: Input Lft Step 2: Lcm  Lft x 30 Step 3: Print Lcm
Flowchart
START
Input
Lft
Lcm  Lft x 30
Print
Lcm
STOP
Dr. Amal Khalifa, 2014

19. Example 2
Write an algorithm and draw a flowchart that will read the radius of a circle and calculate its area.
Dr. Amal Khalifa, 2014

20. Example 2 Input the radius (r) of a circle Calculate the area (A) :
Pseudocode
Input the radius (r) of a circle
Calculate the area (A) :
A  Pi x r x r
Print A
Dr. Amal Khalifa, 2014

21. Example 2 Algorithm Step 1: Input r Step 2: A  Pi x r x r
Step 3: Print A
START
Input r
A  Pi x r x r
Print A
STOP
Dr. Amal Khalifa, 2014

22. Example 3
Write an algorithm and draw a flowchart that will calculate the roots of a quadratic equation
Hint: the roots are:
x1 = (–b + d)/2a and
x2 = (–b – d)/2a
where, d = sqrt ( )
Dr. Amal Khalifa, 2014

23. Example 3
START
Input
a, b, c
d  sqrt(b x b – 4 x a x c)
Print
x1 ,x2
STOP
x1 (–b + d) / (2 x a)
X2  (–b – d) / (2 x a)
Algorithm:
Step 1: Input the coefficients (a, b, c) of the quadratic equation
Step 2: d  sqrt ( )
Step 3: x1  (–b + d) / (2 x a)
Step 4: x2  (–b – d) / (2 x a)
Step 5: Print x1, x2

24. Elements of a Computer System
Hardware
Software
Computer
dr. Amal Khalifa,Fall14

25. Hardware dr. Amal Khalifa,Fall14 Dr. Amal Khalifa - Spring 2012
In my opinion, the students will have a better understanding of what they are doing if they have a little background on the major pieces of a computer and how they work. This is pretty simple and straightforward right now. There's no mention of this being the von Neuman architecture right now, but that should be considered in a revision of these notes.
The blue box represents the core pieces of a computer. The input and output devices are peripheral but important additions.
dr. Amal Khalifa,Fall14
Dr. Amal Khalifa - Spring 2012

26. Memory Unit Ordered sequence of cells or locations
Stores instructions and data in binary
Types of memory
Read-Only Memory (ROM)
Random Access Memory (RAM)
Bits & Bytes
Memory is probably the most important unit for students to understand. This is a brief introduction, but we'll be revisiting memory in future classes. It'll be important for students to see the link between variables and memory.
dr. Amal Khalifa,Fall14

27. Binary Data Bit: A binary digit 0 or 1.
Here are the numbers!!
Binary Data
Bit: A binary digit 0 or 1.
A sequence of eight bits is called a byte.
dr. Amal Khalifa,Fall14

28. ASCII Code
Every letter, number, or special symbol (such as * or {) on your keyboard is encoded as a sequence of bits, each having a unique representation.
The most commonly used American Standard Code for Information Interchange (ASCII).
What about letters/characters?
dr. Amal Khalifa,Fall14

29. Central Processing Unit (CPU)
Executes stored instructions
Arithmetic/Logic Unit (ALU)
Performs arithmetic and logical operations
Control Unit
Controls the other components
Guarantees instructions are executed in sequence
Explain each functional unit in more detail.
dr. Amal Khalifa,Fall14

30. Input and Output Devices
Interaction with humans
Gathers data (Input)
Displays results (Output)
Input and output devices are the pieces of the computer we interact with the most. The students should be familiar with each of these peripherals. In fact, it's a good idea to let the students know that if they aren't familiar with these peripherals that they should be taking the computer literacy class instead.
dr. Amal Khalifa,Fall14

31. Software perform specific tasks Examples : Word processors
System programs
Application programs
loads first when you turn on your PC
Also called the operating system.
The operating system monitors the overall activity of the computer and provides services, such as memory management, input/output activities, and storage management.
perform specific tasks
Examples :
Word processors
spreadsheets, and
games
Both operating systems and application programs are written in programming languages.
dr. Amal Khalifa,Fall14

32. Are Computers Intelligent?
Do we really need to be involved in programming computers?
They have beaten world chess champions.
They help predict weather patterns.
They can perform arithmetic quickly.
So, a computer has an IQ of _____.
Again, try to motivate the students to question why they are in this class. It's not simply to make lots of money, but computers are just plain dumb. The IQ of a computer is 0.
dr. Amal Khalifa,Fall14

33. What is Computer Programming?
Planning or scheduling a sequence of steps for a computer to follow to perform a task.
Basically, telling a computer what to do and how to do it.
A program:
A sequence of steps to be performed by a computer.
Expressed in a computer language.
Now, apply programming to computers.
dr. Amal Khalifa,Fall14

34. Computer Languages A set of used to construct a program.
Symbols (punctuation),
Special words or keywords (vocabulary),
And rules (grammar)
used to construct a program.
Relate computer languages back to natural languages. Students need to appreciate the similarities between the two. Yes, computer languages are somewhat more strict about punctuation and grammar. However, students need to get rid of their fear of the difficulties with the languages.
dr. Amal Khalifa,Fall14

35. Evolution of Programming Languages
Languages differ in
Size (or complexity)
Readability
Expressivity (or writability)
"Level"
closeness to instructions for the CPU
dr. Amal Khalifa,Fall14

36. Machine Language Binary-coded instructions Used directly by the CPU
Lowest level language
Every program step is ultimately
a machine language instruction
Address Contents
2034
2035
2036
2037
2038
2039
2040
2041
2042
Be sure to define "binary" here. Also include definitions of bits and bytes in the discussion as well. Not included on the slide to save space and also it's not important for the students to memorize at this point. Remember, we're just introducing things to the students. Don't expect them to memorize all of this stuff.
dr. Amal Khalifa,Fall14

37. Assembly Language Each CPU instruction is labeled with a mnemonic.
Very-low level language
Almost 1 to 1 correspondence with machine language
Assembler: A program that translates a program written in assembly language into an equivalent program in machine language.
Sample Program
I wonder if this might be getting too gory. Still, I think it's kind of useful.
MUL X,10
ADD X,Y
STO Z,20
SUB X,Z
Mnemonic
Instruction
ADD
dr. Amal Khalifa,Fall14

38. Examples of Instructions in Assembly Language and Machine Language
dr. Amal Khalifa,Fall14

39. High-Level Languages Closer to natural language
Compiler: A program that translates a program written in a high-level language into the equivalent machine language.
dr. Amal Khalifa,Fall14

40. Examples of High-Level Languages
Primary Uses
Pascal
Learning to program
C++
General purpose
FORTRAN
Scientific programming
PERL
Web programming, text processing
Java
Web programming, application programming
COBOL
Business
dr. Amal Khalifa,Fall14

41. The java Language source program. Saved in File ClassName.ja va
dr. Amal Khalifa,Fall14

42. The Code life Cycle!! Edit  compile  run dr. Amal Khalifa,Fall14
In the Java programming language, all source code is first written in plain text files ending with the .java extension. Those source files are then compiled into .class files by the javac compiler. A .class file does not contain code that is native to your processor; it instead contains bytecodes — the machine language of the Java Virtual Machine1 (Java VM). The java launcher tool then runs your application with an instance of the Java Virtual Machine. An overview of the software development process.
dr. Amal Khalifa,Fall14

43. Processing a java program
dr. Amal Khalifa,Fall14

44. IDE
The programs that you write in Java are typically developed using an integrated development environment (IDE).
dr. Amal Khalifa,Fall14

45. That’s all for Today!! Text book [1] chapter 1 (pages 1-13)
dr. Amal Khalifa,Fall14