chapter 01 c++

8/10/2019 Chapter 01 C++

1/45

INTRODUCTION TO

COMPUTERS ANDPROGRAMMING

Chapter 01

1

8/10/2019 Chapter 01 C++

2/45

1.1 Why Program?2

8/10/2019 Chapter 01 C++

3/45

1-3

Why Program?

Computerprogrammable machine designed to

follow instructions

Programinstructions in computer memory to

make it do somethingProgrammerperson who writes instructions

(programs) to make computer perform a task

SO, without programmers, no programs; without

programs, a computer cannot do anything

8/10/2019 Chapter 01 C++

4/45

1.2 Computer Systems: Hardware

and Software4

8/10/2019 Chapter 01 C++

5/45

1-5

Main Hardware Component

Categories:

1. Central Processing Unit (CPU)

2. Main Memory

3. Secondary Memory / Storage

4. Input Devices

5. Output Devices

8/10/2019 Chapter 01 C++

6/45

1-6

Main Hardware Component

Categories

Figure 1-1

8/10/2019 Chapter 01 C++

7/45

1-7

Central Processing Unit (CPU)

Comprised of:

Control UnitRetrieves and decodes program instructions

Coordinates activities of all other parts of computerArithmetic & Logic Unit

Hardware optimized for high-speed numeric calculation

Hardware designed for true/false, yes/no decisions

8/10/2019 Chapter 01 C++

8/45

8/10/2019 Chapter 01 C++

9/45

8/10/2019 Chapter 01 C++

10/45

1-10

Main Memory

AddressesEach byte in memory is identified by

a unique number known as an address.

Above figure, the number 149 is stored in the byte with the address 16, and thenumber 72 is stored at address 23.

8/10/2019 Chapter 01 C++

11/45

1-11

Secondary Storage

Non-volatile: data retained when program is

not running or computer is turned off

Comes in a variety of media:

magnetic: floppy disk, hard drive

optical: CD-ROM, DVD

Flash drives, connected to the USB port

8/10/2019 Chapter 01 C++

12/45

1-12

Input Devices

Devices that send information to the computer

from outside

Many devices can provide input:

Keyboard, mouse, scanner, digital camera,microphone

Disk drives, CD drives, and DVD drives

8/10/2019 Chapter 01 C++

13/45

1-13

Output Devices

Output is information sent from a computer

program to the outside world.

The output is sent to an output device

Many devices can be used for output:

Computer monitor and printer

Disk drives

Writable CD and DVD drives

8/10/2019 Chapter 01 C++

14/45

1-14

SoftwarePrograms That Run

on a Computer

Categories of software:

Operating system: programs that manage thecomputer hardware and the programs that run onthem. Examples: Windows, UNIX, Linux

Application software: programs that provideservices to the user. Examples: word processing,games, programs to solve specific problems

8/10/2019 Chapter 01 C++

15/45

1.3 Programs and Programming

Languages15

8/10/2019 Chapter 01 C++

16/45

1-16

Programs and

Programming Languages

A program is a set of instructions that the

computer follows to perform a task

We start with an algorithm, which is a set of

well-defined steps.

8/10/2019 Chapter 01 C++

17/45

1-17

Example Algorithm for

Calculating Gross Pay

8/10/2019 Chapter 01 C++

18/45

1-18

Machine Language

Although the previous algorithm defines the

steps for calculating the gross pay, it is not

ready to be executed on the computer.

The computer only executes machinelanguageinstructions.

8/10/2019 Chapter 01 C++

19/45

1-19

Machine Language

Machine language instructions are binary

numbers, such as

1011010000000101

Rather than writing programs in machine

language, programmers useprogramming

languages.

8/10/2019 Chapter 01 C++

20/45

1-20

Programs and

Programming Languages

Types of languages:

Low-level: used forcommunication with computerhardware directly. Often writtenin binary machine code (0s/1s)directly.

High-level: closer to humanlanguage

8/10/2019 Chapter 01 C++

21/45

1-21

Some Well-Known Programming

Languages (Table 1-1 on Page 9)

BASIC

FORTRAN

COBOL

C

C++

C#

Java

JavaScript

Python

Ruby

Visual Basic

8/10/2019 Chapter 01 C++

22/45

1-22

From a High-level Program to an

Executable File

a) Create file containing the program with a text editor.

b) Run preprocessor to convert source file directives tosource code program statements.

c) Run compiler to convert source program into machineinstructions.

d) Run linker to connect hardware-specific code tomachine instructions, producing an executable file.

Steps bd are often performed by a single commandor button click.

Errors detected at any step will prevent execution offollowing steps.

8/10/2019 Chapter 01 C++

23/45

1-23

From a High-level Program to an

Executable File

Source Code

Preprocessor

ModifiedSource Code

Compiler

Object Code

Linker

Executable Code

8/10/2019 Chapter 01 C++

24/45

1-24

Integrated Development

Environments (IDEs)

An integrated development environment, or

IDE, combine all the tools needed to write,

compile, and debug a program into a single

software application. Examples are Microsoft Visual C++, Turbo

C++ Explorer, CodeWarrior, etc.

8/10/2019 Chapter 01 C++

25/45

1-25

Integrated Development

Environments (IDEs)

8/10/2019 Chapter 01 C++

26/45

1.4 What Is a Program MadeOf?

26

8/10/2019 Chapter 01 C++

27/45

1-27

What Is a Program Made Of?

Common elements in programminglanguages:

Key Words

Programmer-Defined IdentifiersOperators

Punctuation

Syntax

8/10/2019 Chapter 01 C++

28/45

1-28

Program 1-1

1 // This program calculates the user's pay.2 #include 3 using namespace std;45 int main()6 {7 double hours, rate, pay;8

9 // Get the number of hours worked.10 cout > hours;1213 // Get the hourly pay rate.14 cout > rate;

1617 // Calculate the pay.18 pay = hours * rate;1920 // Display the pay.21 cout

8/10/2019 Chapter 01 C++

29/45

1-29

Key Words

Also known as reserved words

Have a special meaning in C++

Can not be used for any other purpose

Key words in the Program 1-1: using,

namespace, int, double, and return.

8/10/2019 Chapter 01 C++

30/45

1-30

1 // This program calculates the user's pay.2 #include 3 using namespace std;45 int main()6 {7 double hours, rate, pay;



8/10/2019 Chapter 01 C++

31/45

P D fi d

8/10/2019 Chapter 01 C++

32/45

1-32




8/10/2019 Chapter 01 C++

33/45

1-33

Operators

Used to perform operations on data

Many types of operators:

Arithmetic - ex: +,-,*,/

Assignmentex: =

Some operators in Program1-1:

> = *

8/10/2019 Chapter 01 C++

34/45

1-34

Operators




8/10/2019 Chapter 01 C++

35/45

1-35

Punctuation

Characters that mark the end of a statement,

or that separate items in a list

In Program 1-1: ,and ;

8/10/2019 Chapter 01 C++

36/45

8/10/2019 Chapter 01 C++

37/45

1-37

Syntax

The rules of grammar that must be followed

when writing a program

Controls the use of key words, operators,

programmer-defined symbols, and punctuation

8/10/2019 Chapter 01 C++

38/45

1-38

Variables

A variable is a named storage location in thecomputers memory for holding a piece ofdata.

In Program 1-1 we used three variables: The hoursvariable was used to hold the

hours worked

The ratevariable was used to hold the pay

rate Thepayvariable was used to hold the gross

pay

8/10/2019 Chapter 01 C++

39/45

1-39

Variable Definitions

To create a variable in a program you must write

a variable definition (also called a variable

declaration)

Here is the statement from Program 1-1 that

defines the variables:

double hours, rate, pay;

8/10/2019 Chapter 01 C++

40/45

1-40


There are many different types of data, whichyou will learn about in this course.

A variable holds a specific type of data.

The variable definition specifies the type ofdata a variable can hold, and the variable

name.

8/10/2019 Chapter 01 C++

41/45

1-41


Once again, line 7 from Program 1-1:

double hours, rate, pay;

The word doublespecifies that the variables

can hold double-precision floating point

numbers. (You will learn more about that in

Chapter 2)

8/10/2019 Chapter 01 C++

42/45

1.5 Input, Processing, andOutput

42

8/10/2019 Chapter 01 C++

43/45

1-43

Input, Processing, and Output

Three steps that a program typically performs:

1) Gather input data: from keyboard

from files on disk drives

2) Process the input data

3) Display the results as output: send it to the screen

write to a file

8/10/2019 Chapter 01 C++

44/45

8/10/2019 Chapter 01 C++

45/45

The Programming Process

chapter 01 c++

Documents