1. Programming Languages
Chapter 1:
An Overview of
Computers and
Programming Languages
Ed. 8
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2. Objectives In this chapter you will:
Learn about different types of computers
Explore the hardware and software components of a computer system
Learn about the language of a computer
Learn about the evolution of programming languages
Examine high-level programming languages
Discover what a compiler is and what it does
Examine a C++ program
Explore how a C++ program is processed
Learn what an algorithm is and explore problem-solving techniques
Become aware of structured design and object-oriented design programming methodologies
Become aware of Standard C++ and ANSI/ISO Standard C++, C++11, and C++14

3. Without software, a computer is useless
Introduction
Without software, a computer is useless
Software is developed with programming languages
C++ is a programming language
C++ is suited for a wide variety of programming tasks

4. A Brief Overview of the History of Computers
Early calculation devices
Abacus – invented in Asia, used Babylon, China & Europe
Pascaline
Leibniz device
Jacquard’s weaving looms
Babbage machines: difference and analytic engines
Hollerith machine
Early computer-like machines
Mark I – IBM & Harvad University, ‘44, weighted 50 tons, 18,000 tubes
Electronic Numerical Integrator and Calculator (ENIAC)
The computer we know today are based on Von Neumann architecture in late ‘40s
Universal Automatic Computer (UNIVAC) – ‘51
Transistors and microprocessors

5. Categories of Computers
Mainframe computers
Midsize computers
Microcomputers
personal computers (PC) – 1st Apple computer ‘77 Stephen Wozniak & Steven Jobs, PC - IBM ‘81
PDAs, pocket computers
Cell phones, mobile phones
ipods combined with PDAs and phones

7. CPU (Central Processing Unit)
CU (Control Unit):
Fetches and decodes instructions
Controls flow of information in and out of MM (Main Memory)
Controls operation of internal CPU components
PC (program counter): points to next instruction to be executed

8. CPU (Central Processing Unit) (continued)
IR (instruction register): holds instruction currently being executed
ALU (arithmetic logic unit): carries out all arithmetic and logical operations

9. Main Memory or Random Access Memory - RAM
Directly connected to the CPU
All programs must be loaded into main memory before they can be executed
All data must be brought into main memory before it can be manipulated
When computer power is turned off, everything in main memory is lost

11. Secondary storage: Device that stores information permanently
Examples of secondary storage:
Hard disks
USB flash drive
CD-ROMs
SD - (Secure Digital Card) is an ultra small flash memory carddesigned to provide high-capacity memory in a small size. SD cardsare used in many small portable devices such as digital video camcorders, digital cameras, handheld computers, audio players and mobile phones.
Floppy disks
Zip disks
Tapes

12. Input devices feed data and programs into computers - Include:
Input/Output Devices
Input devices feed data and programs into computers - Include:
Keyboard
Mouse
Scanner
Camera
Secondary storage
Output devices display results. They include:
Monitor
Printer

13. Software Software: Programs that do specific tasks
System programs take control of the computer, such as an operating system
Operating system monitors the overall activity of the computer and provides services such as:
Memory management
Input/output activities
Storage management
Application programs perform a specific task
Word processors
Spreadsheets
Games

14. The Language of a Computer
Analog signals: varying continuous wave forms
Digital signals are sequences of 0s and 1s
Machine language: language of a computer
A sequence of 0s and 1s
Binary digit (bit):
The digit 0 or 1
Binary code:
Byte:
A sequence of eight bits

15. The Language of a Computer
TABLE 1-1 Binary Units
Unit
Symbol
Bits/Bytes
Byte
8 bits
Kilobyte KB
210 bytes = 1024 bytes
Megabyte MB
1024 KB = 210 KB = 220 bytes = 1,048,576 bytes
Gigabyte GB
1024 MB = 210 MB = 230 bytes = 1,073,741,824 bytes
Terabyte TB
1024 GB = 210 GB = 240 bytes = 1,099,511,627,776 bytes
Petabyte PB
1024 TB = 210 TB = 250 bytes = 1,125,899,906,842,624 bytes
Exabyte EB
1024 PB = 210 PB = 260 bytes = 1,152,921,504,606,846,976 bytes
Zettabyte ZB
1024 EB5 210 EB = 270 bytes = 1,180,591,620,717,411,303,424 bytes
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16. Coding Schemes
ASCII (American Standard Code for Information Interchange) – Appendix C
128 characters
A is encoded as (66th character)
3 is encoded as
Number systems
The decimal system (base 10) is used in our daily life
The computer uses the binary (or base 2) number system

17. Coding Schemes (continued)
EBCDIC
Used by IBM
256 characters
Unicode
65536 characters
Two bytes (16 bits) are needed to store a character.

18. Programming Language Evolution
Early computers were programmed in machine language
To calculate
wages = rates * hours
in machine language:
// Load rates
// Multiply by hours
// Store wages

19. Assembly language instruction are mnemonic
Assembler: translates a program written in assembly language into machine language
wages = rates * hours
in machine language:
// Load-LOAD rates
// Multiply-MULT by hours
// Store-STOR wages

20. Program Example
Using the assembly language instructions, the equation
wages = rates * hours
can be written as follows:
LOAD rate
MULT hour
STOR wages

21. The equation wages = rate * hours can be written in C++ as:
High-Level Languages
High-level languages include Basic, FORTRAN, COBOL, C, C++, C, C#, Java, Pascal and Python
Compiler: translates a program written in a high- level language machine language
The equation wages = rate * hours can be written in C++ as:
wages = rate * hours;

22. Processing a C++ Program (1 of 4)
#include <iostream>
using namespace std;
int main() {
cout << "My first C++ program." << endl;
return 0; }
Sample Run:
My first C++ program.

23. Processing a C++ Program (2 of 4)
Steps needed to process a C++ program
Use a text editor to create the source code (source program) in C++
Include preprocessor directives
Begin with the symbol # and are processed by the preprocessor
Use the compiler to:
Check that the program obeys the language rules
Translate the program into machine language (object program)
Use an integrated development environment (IDE) to develop programs in a high-level language
Programs such as mathematical functions are available
The library contains prewritten code you can use
A linker combines object program with other programs in the library to create executable code
The loader loads executable program into main memory
The last step is to execute the program

24. Processing a C++ Program (3 of 4)
IDEs are quite user friendly
Compiler identifies the syntax errors and also suggests how to correct them
Build or Rebuild is a simple command that links the object code with the resources used from the IDE

25. Processing a C++ Program (4 of 4)
Steps needed to process a C++ program
Use a text editor to create the source code (source program) in C++
Include preprocessor directives
Begin with the symbol # and are processed by the preprocessor
Use the compiler to:
Check that the program obeys the language rules
Translate the program into machine language (object program)
Use an integrated development environment (IDE) to develop programs in a high-level language
Programs such as mathematical functions are available
The library contains prewritten code you can use
A linker combines object program with other programs in the library to create executable code
The loader loads executable program into main memory
The last step is to execute the program
FIGURE 1-2 Processing a C++ program
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26. To execute a program written in a high-level language such as C++
Processing a Program
To execute a program written in a high-level language such as C++
1. Use an editor to create a source program in C++
2. Use the compiler to
Check that the program obeys the rules
Translate into machine language (object program)

27. Processing a Program (continued)
3. Software Development Kit (SDK) may be used to create a program
Linker:
Combines object program with other programs provided by the SDK to create executable code
4. Loader:
Loads executable program into main memory
5. The last step is to execute the program

28. Three C++ Program Stages
myprog.cpp
myprog.obj
myprog.exe
SOURCE
OBJECT
EXECUTABLE
written in
machine
language
C++
via compiler
via linker
other code
from libraries,
etc.

29. Programming is a process of problem solving Problem solving techniques
Analyze the problem
Outline the problem requirements
Design steps (algorithm) to solve the problem
Algorithm:
Step-by-step problem-solving process - series of actions in a specific order
Solution achieved in finite amount of time
Example: "Rise and Shine" algorithm
Get out of bed, take off pajamas, take a shower, get dressed, eat breakfast, carpool to work

30. Problem Solving Process
Step I - Analyze the problem
Outline the problem and its requirements
Design steps (algorithm) to solve the problem
Step II - Implement the algorithm
Implement the algorithm in code
Verify that the algorithm works
Step III - Maintenance
Use and modify the program if the problem domain changes

31. Step 1. Analyze the Problem
Thoroughly understand the problem
Understand problem Step 1 requirements
Does program require user interaction?
Does program manipulate input data?
What is the output looks like?
If the problem is complex, divide it into subproblems
Analyze each subproblem as above
Step 1

32. Step 2. Algorithms Design
Algorithm is a step by step procedure for solving a problem in terms of
Series of actions in specific order
The actions executed
The order in which actions execute
Example: "Rise and Shine" algorithm
Get out of bed, take off pajamas, take a shower, get dressed, eat breakfast, carpool to work
Experience has shown that the most difficult part of solving a problem on a computer is developing the algorithm for the solution.
Program control (flow of control)
Specifying the order in which actions (statements or instructions) execute
Control structures help specify this order

33. Program flowchart (programming logic)
Graphical representation of an algorithm.
The detailed flowchart provides a detailed picture of a process by mapping all of the steps and activities that occur in the process.
Provides an essential tool to understanding programming logic
Designing a flowchart helps the coding easier.
Drawn using symbols connected by arrows called flowlines
Rectangle symbol (action symbol)
Indicates any type of action
Diamond symbol (decision symbol)
Indicates that a decision to be made
Oval symbol:
Indicates beginning or end of a program, or a section of code (circles)
Indicates a portion of an algorithm
add grade to total
add 1 to counter
total = total + grade;
counter = counter + 1;

34. Flowchart
Flowchart of sequence structure: Two actions performed in order
When drawing a portion, small circles is used
add grade to total
add 1 to counter
total = total + grade;
counter = counter + 1;
The program flowchart can be likened to the blueprint of a building.
As we know a designer draws a blueprint before starting construction on a building.
Similarly, a programmer prefers to draw a flowchart prior to writing a computer program.
As in the case of the drawing of a blueprint, the flowchart is drawn according to defined rules and using standard flowchart symbols prescribed by the American National Standard Institute, Inc. See detail Flow Chart Definition.
Fig. 5.1 Flowcharting C#’s sequence structure.
When flowcharting a complete algorithm
Oval containing "Begin" is first symbol
Oval containing "End" is last symbol
When drawing a portion, small circles used
Useful for algorithms.

35. Pseudocode
Pseudocode (pronounced SOO-doh-kohd) is a detailed yet readable description of what a computer program or algorithm must do, expressed in a formally-styled natural language rather than in a programming language. 
Similar to everyday English
Not actually executed on computers
pseudocode is sometimes used as a detailed step in the process of developing a program
a notation that combines some of the structure of a programming language, such as IF-ELSE and DO WHILE constructs, with a natural language, such as plain English.
is an informal high-level  informal language of a computer program.
artificial, informal language
helps develop algorithms
pseudocode is often used to “think out” a program during the program-design process
Easy to convert into corresponding program language
Consists only of executable statements
Declarations are not executable statements
Actions: input, output, calculation

36. Step 2. Design an Algorithm
If problem was broken into subproblems
Design algorithms for each subproblem
Check the correctness of algorithm
Can test using sample data
Some mathematical analysis might be required
Step 2

37. Once the algorithm is designed and correctness verified
Step 3. Write the Code
Once the algorithm is designed and correctness verified
Write the equivalent code in high-level language
use text editor
Step 3

38. Step 4. Compiling and Linking
Run code through compiler
If compiler generates errors
Look at code and remove errors
Run code again through compiler
If there are no syntax errors
Compiler generates equivalent machine code
Linker links machine code with system resources (libraries)
Step 4

39. Step 5. The Loader and Executing
Once compiled and linked, loader can place program into main memory for execution
The final step is to execute the program
Compiler guarantees that the program follows the rules of the language
Does not guarantee that the program will run correctly
Step 5

40. Various Types of Errors
Design errors occur when specifications are wrong
Compile errors occur when syntax is wrong
Run-time errors result from
incorrect assumptions, e.g. x / 0
incomplete understanding of the programming language, or
unanticipated user errors.
count == count + 1
if (count = 20)

41. Design an algorithm to find the perimeter and area of a rectangle
Example Rectangle
Design an algorithm to find the perimeter and area of a rectangle
The perimeter and area of the rectangle are given by the following formulas:
perimeter = 2 * (length + width)
area = length * width

42. Algorithm (in pseudocode):
Example 1-1
Algorithm (in pseudocode):
Get length of the rectangle
Get width of the rectangle
Find the perimeter using the following equation:
perimeter = 2 * (length + width)
4. Find the area using the following equation:
area = length * width

43. Example 1- 2
Algorithm (in pseudocode):
Every salesperson has a base salary
Salesperson receives $10 bonus at the end of the month for each year worked if he or she has been with the store for five or less years
The bonus is $20 for each year that he or she has worked there if over 5 years

44. Example 1-3 (continued)
Additional bonuses are as follows:
If total sales for the month are $5000- $10000, he or she receives a 3% commission on the sale
If total sales for the month are at least $10000, he or she receives a 6% commission on the sale

45. Algorithm (in pseudocode): Get baseSalary Get noOfServiceYears
Example 1-3 (continued)
Algorithm (in pseudocode):
Get baseSalary
Get noOfServiceYears
Calculate bonus using the following formula:
if (noOfServiceYears is less than or equal to five)
bonus = 10 * noOfServiceYears
otherwise
bonus = 20 * noOfServiceYears
4. Get totalSale

46. 5. Calculate additionalBonus as follows:
Example 1-3 (continued)
5. Calculate additionalBonus as follows:
if (totalSale is less than 5000)
additionalBonus = 0
otherwise
if(totalSale is >= to
5000 and totalSale < 10000)
additionalBonus = totalSale · (0.03)
additionalBonus = totalSale · (0.06)
6. Calculate payCheck using the equation
payCheck = baseSalary + bonus + additionalBonus

47. Calculate each student’s grade
Example 1-5 (1 of 4)
Calculate each student’s grade
There are 10 students in a class
Each student has taken five tests
Each test is worth 100 points
Design algorithms to:
Calculate the grade for each student and class average
Find the average test score
Determine the grade
Use the provided data: students’ names and test scores

48. Algorithm to determine the average test score
Example 1-5 (2 of 4)
Algorithm to determine the average test score
Get the five test scores
Add the five test scores
The sum of the test scores is represented by sum
Suppose average stands for the average test score:
average = sum / 5;

49. Algorithm to determine the grade:
Example 1-5 (3 of 4)
Algorithm to determine the grade:
if average is greater than or equal to 90
grade = A
otherwise
if average is greater than or equal to 80 and less than 90
grade = B
if average is greater than or equal to 70 and less than 80
grade = C
if average is greater than or equal to 60 and less than 70
grade = D
grade = F

50. Main algorithm (in pseudocode) is presented below:
Example 1-5 (4 of 4)
Main algorithm (in pseudocode) is presented below:
totalAverage = 0;
Repeat the following for each student:
Get student’s name
Use the algorithm to find the average test score
Use the algorithm to find the grade
Update totalAverage by adding current student’s average test score
Determine the class average as follows:
classAverage = totalAverage / 10

51. Structured Programming
Structured design:
Dividing a problem into smaller subproblems
Structured programming
Implementing a structured design
The structured design approach is also called
Top-down design
Stepwise refinement
Modular programming

52. Structured Programming
Stacked building blocks
Overlapping building blocks (illegal in structured programs)
Nested building blocks
Combination of control structures:
Stacking
Placing one after another
Nesting
Inserting of one structure into another
Fig. Stacked, nested and overlapped building blocks.

53. Object-Oriented Programming
Identify components called objects
Each object consists of data and operations on that data
Specify relevant data and possible operations to be performed on that data
An object combines data and operations on the data into a single unit
To create operations:
Write algorithms and implement them in a programming language

54. OBJECT Operations Data What is an object? set of functions
internal state
Operations
Data

55. Object-Oriented Programming (continued)
A programming language that implements OOD (Design) is called an object-oriented programming (OOP) language
Before: learn
how to represent data in computer memory,
how to manipulate data, and
how to implement operations
then write algorithms and implement them in a programming language

56. Object-Oriented Design
A technique for developing a program in which the solution is expressed in terms of objects - self- contained entities composed of data and operations on that data.
cin
cout
>>
<<
get
Private data
setf
Private data . .
ignore
setw 56

57. Object-Oriented Programming (continued)
Learn how to combine data and operations on the data into a single unit called an object
C++ was designed to implement OOD
OOD is used in conjunction with structured design

58. Two Programming Methodologies
Functional Object-Oriented
Decomposition Design
OBJECT
Operations
Data
FUNCTION
FUNCTION
OBJECT
Operations
Data
OBJECT
Operations
Data
FUNCTION

59. An object contains data and operations
checkingAccount
OpenAccount
Private data:
accoutNumber
balance
WriteCheck
MakeDeposit
IsOverdrawn
GetBalance

60. C++ designed by Bjarne Stroustrup at Bell Laboratories in early 1980s
ANSI/ISO STANDARD C++
C++ evolved from C
C++ designed by Bjarne Stroustrup at Bell Laboratories in early 1980s
C++ programs were not always portable from one compiler to another, so
In mid-1998, ANSI/ISO C++ language standards were approved
the book focuses on the latest syntax of ANSI/ISO C++
Second standard (the C++ code cleaner and more effective) called C++11, was approved in 2011
New data type long long to deal with large integers
Auto declaration of variables using initialization statements
Enhancement the functionality of for loops effectively work with arrays and containers
C++14 is an update over C++ was approved in 2014.

61. Computer system has hardware and software
Summary
Computer: an electronic device that can perform arithmetic and logical operations
Computer system has hardware and software
Central processing unit (CPU): brain
Primary storage (RAM) is volatile; secondary storage (e.g., disk) is permanent
Operating system monitors the overall activity of the computer and provides services

62. Program flowchart (programming logic)
Summary
Various kinds of languages, such as machine language, assembly, high-level
Algorithm: step-by-step problem-solving process - series of actions in a specific order; solution in finite amount of time.
Program flowchart (programming logic)
Graphical representation of an algorithm.
The problem-solving process has three steps:
Analyze problem and design an algorithm
Implement the algorithm in code
Maintain the program

63. Object: data and operations on those data
Summary
Structured design:
Problem is divided into small subproblems
Each subproblem is solved
Combine solutions to all subproblems
Object-oriented design (OOD): a program is a collection of interacting objects
Object: data and operations on those data