02 Intro to Cpp

8/2/2019 02 Intro to Cpp

1/101


2/101

Machine Language

Ada

PascalFortranCOBOL

Assembly Language

Smalltalk

Visual BasicBASIC

JavaC and C++

Programming Languages

Programming languages are artificial languagescreated to tell the computer what to do

They consist of vocabulary and a set of rules

(grammar/syntax) to write programs

The software development life cycle (SDLC) is anorganized method of software development


3/101

C++ Predecessors

Early procedural languages included

FORTRAN: Formula Translation

ALGOL: Algorithmic Language

COBOL: Common Business Oriented LanguageBASIC: Beginners All-purpose Symbolic

Instruction Code

Pascal

CSmalltalk, Simula, etc. were the object-oriented

predecessors of C++

Thi d i d F h


4/101

The Evolution

of Programming

Languages

Third- eneration and Fourth-Generation (High-Level) Languages


5/101

First-Generation Languages

Machine language:

Consists of binary numbers(0s and 1s)

Is the earliest programming

language Is the only language the

computer understandswithout translation

It is machine dependent;each family of processorshas its own machinelanguage


6/101

Second-Generation Languages

Assembly language:

Resembles machinelanguage

Is a low-level language

Uses brief abbreviations forprogram instructions.

Abbreviations are calledmnemonics

A program is written insource code (text file) andtranslated into machine

language by an assembler


7/101

Third-Generation Languages

Procedural languages:

Are high-level languages that tell the computerwhat to do and how to do it

Create programs at a high level of abstractionAre easier to read, write, and maintain than

machine and assembly languages

Use a compiler or interpreter to translate code

Fortran and COBOL are third-generationlanguages


8/101

Compilers and Interpreters

An interpreter translates source code one line at a timeandexecutes the instruction

A compiler is a program that changes source code to objectcode, all in one shot

Example of an interpreted language: BASIC; a compiled

language: C

Th t t i i th


9/101

The reat o tware risis o the60s

Spaghetti Code and the Great Software Crisis:goto statements resulted in programs that were

difficult to follow

This made them difficult to modify, maintain, andeven develop!

This problem led to the software crisis of the1960s

Programs were not ready on timePrograms exceeded their budgets

Programs contained too many errors

Customers were not satisfied

Management was also very frustrated!

t t d P i t th


10/101

tructured Programming to therescue

Structured programming languages:

Were developed to improve software

developmentInclude Algol and Pascal

Are well-structured and organized

Forbid the use of goto statementsUse three fundamental control structures

Sequence, Selection, Repetition

M d l P i L


11/101

Modular Programming Languagesdeveloped in the 70s

Modular programming languages:

Were developed because of problems in

structured programming languagesAre used to create programs that are divided

into separate modules

Each module carries out a special function

Require specified input to produce specifiedoutput


12/101

Fourth-Generation Languages Fourth-generation languages are non-procedural, high-level

specification languages

They do not force programmers to follow procedures to produce results(theyre very close to English, sometimes)

Types of fourth-generation languages include:

Report generators

Languages for printing database reports (generate a programto generate

the report) Query languages

Languages for getting information out of databases (generate a programtoprocess a query or generate a form)

Also include visually-oriented languages

More ambitious 4GL environments attempt to automatically generatewhole systems from the outputs of CASE tools, specifications of screensand reports, and possibly also the specification of some additionalprocessing logic, including data flow diagrams, entity relationshipdiagrams, entity life history diagrams

Fifth-generation languages

These include artificial intelligenceand neural networksorientedlanguages


13/101

SKIP: Object-Oriented Programming

Object-oriented programming (OOP):

Relies on component reusability

The ability to produce program modules thatperform a specific task

Eliminates the distinction between programsand data

Uses objects that contain data andprocedures


14/101

SKIP: Objects Objects are units of information that contain data as

well as methods that process and manipulate the data

Classes of objects:

Hierarchy or category of objects

Objects at the top of the category are broader in

scope than the subclass objectsObjects near the bottom are narrower in scope

Inheritancerefers to an objects capacity to pass onits characteristics to its subclasses


15/101


16/101

3GL Programming Languages

Most high-level programming languages canbe categorized into one of three maincategories:

Procedural Languages (FORTRAN, BASIC,COBOL, Pascal, etc.)

Object-Oriented Languages (Smalltalk, Effiel,etc.)

Hybrid Languages allow both OO andProcedural (such as C++)


17/101

3GL: Procedure-oriented (structured) languages Programmers concentrate on the procedures used in the

program

Procedure: a logically consistent set of instructions which is usedto produce one specific result

3GL: Object-oriented languages

Items are represented using self-contained objects

Can be used to create programs for graphical windowsenvironments

4GLs: fourth-generation languages Permit users to access and format information without the

need for writing any procedural code

Use high-level English-like instructions to specify what to do, not

how to do it .

3GL vs. 4GL


18/101

Procedural Programming Basics

The purpose of most applicationprograms is to process data toproduce specific results

Basic procedural operations.


19/101

What Can a Procedural Program Do?

A linear, procedural program is structured toinstruct a computer to:

Read InputCalculate

Store data

Write Output

Work in a sequential progression (Sequence)Compare and branch (Selection)

Iterate or Loop (Repetition)

Ad t f P d l


20/101

Advantages of ProceduralProgramming

Easier to test and debug Structured walkthroughs of the code

goto-less

I.e., theyre well-structured and include the three

fundamental control structures Standard method for solving a problem

A single program can be written by more than oneprogrammer

By dividing the program up into modules

Programs can share routines (again, because ofmodularization)


21/101

Whats structured programming?

A Structure is One or More Instructions

(Flowchart Symbols) Combined According toRules

E.g., only one point of entry and exit

Structured programming is a set of rules that

prescribe good style habits for programmer.

An organized, well structured code

Easily sharable; easy to debug and test

Requires shorter time to develop, test, and update

The key idea is that any numerical algorithm can

be composed using the three fundamental control

structures:

Sequence, selection, and repetition

a re e es or r ng a


22/101

a re e u es or r ng aStructured Program?

3 basic control structures:

Sequence

Selection (decision)

Repetition (looping or iteration)


23/101

Modularization

Modular Program: a program consisting ofinterrelated segments arranged in a logical andunderstandable form

Easier to develop, correct, and modify than otherkinds of programs

Module: a small segment which is designed toperform a specific task

A group of modules is used to construct amodular program

Modular Programming


24/101

Modular Programming Behind most software development over the last century Encourages subroutines Large programs are divided by functional parts into

subroutines or modules Go to instructions only permitted within subroutines Three objectives when creating routines:

Smaller, simpler routines Breakup complex routines into simple functions

Strong cohesion Routine does one function such as printing

Instructions are closely related

Loose coupling Non-existent or weak connection between routines

One routine does not depend on other routines


25/101

SUBPROGRAM (function)SUBPROGRAM1 . . .

SUBPROGRAM1

a meaningful collection

of SEQUENCE,SELECTION, REPETITION

(LOOP), or SUBPROGRAMS


26/101

Introduction to C++

Modules in C++ can be classes or functions

Function: accepts an input and produces an

output by processing the input in some fashion A functions processing is encapsulatedand

hiddenwithin the function


27/101

A Multiplying Function


28/101

Classes and Functions

Function: encapsulates a set of operations, whilea classencapsulates data plus one or more sets

of operations Class: contains both data and functions used to

manipulate the data

Identifier: a name given to an element of the

language, such as a class or function

The o tware Development Li e


29/101

The o tware Development Li eCycle (SDLC)

The SDLC was introduced in the 1970s to addressproblems in creating programs

It provides an organized plan for breaking down thetask of program development into manageable parts

Five phases of the SDLC:

1. Defining the problem

2. Designing the program

3. Coding the program

4. Testing, debugging, and formalizing the program

5. Implementing and maintaining the program


30/101

Phase 1: Defining the Problem

The first step in program development

What do you want to solve? What is the objective and question? Get the requirements from the client (possibly other software

engineers)

Systems analysts provide program specifications (specs) to the

programmers The specs define:

Input data

Processing Output

Including the appearance of the user interface Software engineers need clear specifications (as opposed to

requirements):

Clear, specific statement of goal Expected output Expected input


31/101

Phase 2: Designing the Program

Programmers create the programs design

Top-down designfocuses on the programs main goal(main routine), then breaks the program into manageablecomponents (subroutines/modules)

Control structures are used to see how each subroutine

will do its job Makes programming easier to develop, debug, and

maintain

Developing an algorithm, which is a step-by-step descriptionof how to arrive at a solution

Program design tools:

Structure charts show the top-down design

Flow charts show the logic of program

Pseudocode alternative to flow charts


32/101

Structured Design

Structured programming implements structured design

Control structures are logical constructs that specifyhow the instructions in a program are to be executed

Three fundamental types of control structures:

Sequence control structure Instructions areexecuted in the order in which they appear

Selection control structures The programbranches to different instructions depending on

whether a condition is met; IFTHENELSE Repetition control structure The program

repeats the same instructions over and over; DO-WHILE and DO-UNTIL

S Ch d Fl h


33/101

Structure Chart

Flowchart

Structure Chart and Flowchart

Ph 3 C di th P


34/101

Phase 3: Coding the Program

Codingrequires the translation of the algorithm intospecific program instructions

An appropriate programming language is chosen,

and the code is typed according to its syntax rules Documentationis created for future use

Best if the documentation is done in-line using a tool likeJavaDoc, Doxygen, etc.

The variable names and definitions, a description ofthe files needed, and the layout of the output areproduced

A user manualis developed to explain how the

program works

Phase 4: Testing and Debugging the


35/101

Phase 4: Testing and Debugging theProgram

Testing and debugging eliminate all errors

Syntax and logic errors are corrected Debugging is the process of eliminating errors

Phase 5: Implementing and


36/101

Phase 5: Implementing andMaintaining the Program

The program is:

Tested by usersThoroughly documented

Maintained and evaluated regularly

Al ith


37/101

Algorithms

Algorithm: A step-by-step sequence of instructionsthat must terminate

Pseudocode

Use of English-like phrases to describe an algorithm

Formula

Use of mathematical equations to describe analgorithm

FlowchartUse of diagrams that employ symbols to describe an

algorithm

P D i P


38/101

Program Design Process

AL-KHOWARIZMI

Grace M. HopperFirst Bug

Algorithm Design

(underlying logic of program)

Program Composition

Debug & test

(error free & reliable)

Documentation

Maintenance

75% of costs!

Whats an Algorithm?


39/101

Whats an Algorithm?

A predetermined series of

instructionsfor carrying out atask in a finite number of steps

I.e., Baking A Cake!

Two commonly used tools tohelp document the program

logic (the algorithm):Flowcharts and Pseudocode.

Generally, Flowcharts workwell for small problems butPseudocode is used for larger

problems


40/101

How to make a plan ?

Do a hand calculation (brainstorming!)

Make a flowchart

Visio or dia

Write the Pseudocode

Flowchart: Symbolic Representation of Algorithms


41/101

Flowchart: Symbolic Representation of Algorithms

Flowchart: A graphic representation of an algorithm

often used in the design phase of programming to work outthe logical flow of a program

Uses symbols to represent each logical step of thealgorithm.

The order in which the steps are carried out is indicated byconnecting flow lines

Use a few, basic flowchart symbols

Follow UML (Unified Modeling Language)

Standard defined by OMG group:http://www.omg.org/technology/documents/formal/uml.htm

Basic Flowchart
http://www.omg.org/technology/documents/formal/uml.htmhttp://www.omg.org/technology/documents/formal/uml.htm


42/101

Basic FlowchartSymbols

Some basic symbols:


43/101

Basic Control Structures

a sequenceis a series of statements that execute one afteranother

selection (branch) is used to execute different statements

depending on certain conditions

repetition (looping)is used to repeat statements whilecertain conditions are met.

a subprogram (module) is used to break the program

into smaller units

SEQUENCE


44/101

SEQUENCE

Can contain any symbolexcept for the decision orloop symbol

Steps are executed insequence with noinstruction changing theorder

Flow lines connect eachinstruction


45/101

SELECTION(branch)

O ( )


46/101

REPETITION (loop)

Pseudocode


47/101

Logical steps

Written in English

and symbols,

terms, etc.

Indenting forlogical structures

begin some gamedisplay instructionspick a number between 1 and 100

repeat turn until number is guessedor seven turns are completed

input guess from userrespond to guess

end repeat

end some gamedisplay end message

Looks like BASIC(Chris Clark)

Pseudocode

Pseudocode or three control


48/101

Pseudocode or three controlconstructs

What is Pseudocode?


49/101

What is Pseudocode? An alternative to flowcharting

Represents logic in an English-like manner Rules

Avoid the use of words peculiar to a particular programminglanguage

Indent lines to make the pseudocode easy to read andunderstand

Show key words (Move, Write, Read) in a different color, font, orcapitalized

Punctuation is optional

End every If with EndIf Begin every loop with a Loop instruction; End every loop with

EndLoop

Main routine is to be shown first

Terminate all routines with an End instruction (e.g., EndMain)

Example 1


50/101

Write an algorithm in pseudocode that findsthe average of two numbers

Example 1

SKIP: Average of two


51/101

StartAverageOfTwo

0. Input:Two numbers

1. Add the two numbers2. Divide the result by 2

3. Return the result by step 2

End

SKIP: Average of two

Example 2


52/101

Write an algorithm to change a numericgrade to a pass/no pass grade.

Example 2

SKIP: Pass/No Pass Grade


53/101

Pass/NoPassGradeInput:One number

1. if (the number is greater than or equal to 70)

then

1.1 Set the grade to passelse

1.2 Set the grade to nopass

End if

2. Return the grade

End

SKIP: Pass/No Pass Grade

Flowchart & Pseudocode


54/101

Flowchart & Pseudocode

Start

Sum=0Count = 0

InputGrade

Moregrades?

Sum = Sum + GradeCount = Count + 1

Average = Sum/Count

Stop

No

Yes

FlowchartPseudocode

BEGIN Average Gradesum=0count = 0

DOINPUT gradeIF grade < 0 EXITsum = sum + gradecount = count +1

END DOIF count > 0 THEN

average = sum/countELSEaverage = 0

END IFEND Average Grade

Your first program in C++


55/101

Your first program in C++

hello.cpp compiler a.out

Writing a program in Linux involves three steps

e a s o a yp ca ++ nv ronmen


56/101

e a s o a yp ca ++ nv ronmenPhases of C++ Programs:

1. Edit2. Preprocess

3. Compile

4. Link

5. Load & Execute LoaderPrimaryMemory

Program is created in

the editor and stored

on disk.

Preprocessor program

processes the code.

Loader puts program

in memory.

CPU takes each

instruction and

executes it, possibly

storing new data

values as the programexecutes.

Compiler

Compiler creates

object code and stores

it on disk.

Linker links the object

code with the libraries,

creates a.out and

stores it on disk

Editor

Preprocessor

Linker

CPU

PrimaryMemory

.

.

.

.

.

.

.

.

.

.

.

.

Disk

Disk

Disk

Disk

Disk

Code (write) the program


57/101


Carefully enter the code

Remember most C++ statements end with a ;

Commands are in lower case

DEMO: 1 Edit


58/101

DEMO: 1. Edit

Start up an editor (emacs) to edit a file called hello.cpp

Type the following into the file:

#include

using namespace std;

int main(void){

cout


59/101

DEMO: 2. Compile

Compile your program

g++ hello.cpp

This tells the computer to call the compiler tocreate the program

The compiler is a program that takes the codethat you write and translates it into machine

languageMachine code is made up of many simple

instructions composed of 0s and 1s

DEMO: 3 Execute


60/101

DEMO: 3. Execute

You should now have a file called a.out

inside your directory

This file is called an executablea.out holds the binary version of your code

(the computer doesnt understand words, just0s and 1s)

To run the program type:./a.out

What does the code mean?


61/101


#include


Allows us to use functions that other peoplehave written to facilitate input and output

Processed by the pre-processor(its called apre-processor directive)

Literally copies and pastes the libraries offunctions that others wrote

This is what makes Java and MFC so powerful!



62/101


int main(void)

Remember, every C++ program is made of one ormore functions

A functionis a piece of code that accomplishes onespecific task

Every executable C++ program has one functioncalled main()

This is where execution (the actual running) of theprogram (i.e., the computer instructions) starts


63/101


int main(void)

When you type ./a.out to run the program you

are essentially telling the computer to call thismain() function

Callinga function means to execute the code inthe function


64/101


int main(void)

The int is the return type of the function.

In other words when it finishes what kind of result

does it give back. A whole number? A character?int means a whole number.

We want to give this number back to tell us if theprogram was sucessfully completed


65/101


int main(void)

The void in the brackets is the parameter list

for this function

The parameter list indicates what this functionneeds to be given from the outset for it to work

void indicates that we give nothing to this

function.



66/101


cout


67/101


return 0;

This is the last line in our program

It basically means that the program is now done

return means to go back to where theprogram was called from0 is used to indicate that it was successfully

completed (a general convention)



68/101


Note also that the code of main() is containedwithin the { }

These {} group code together.

In this case it tells us that all the code between themare part of the main function

#include


int main(void){

cout


69/101

Some Important Terms A source program(.cpp file type) consists of the program statements

comprising a C++ or other programming language program.

An object program (.obj file type) is the result of compiling a source

program.

Header files (.h file type) contain constant, variable, and function

declarations needed by a program.

An executable program is a program that can be run by a computer. Linking adds code from libraries to your file. Collects the object code

from all files in the workspace and puts them into one executableprogram.

A compiler is a program that translates a source program into an

object program. An interpreter is a program that translates individual source program

statements, one at a time, into executable statements. Each statementis executed immediately after translation.

Compiling / Building


70/101

Compiling / Building

(.cpp file)source code

compiler

(.obj file)

object code

(.h files)

linked tolibraries

executable

file

object code fromother source files

Error error does not compute!


71/101

Error, error does not compute! Syntax Errors Typing Errors

Errors in spelling and grammar (syntax). Doag. Bites, Man

You can use the compiler or interpreter to uncover syntaxerrors.

You must have a good working knowledge of error messagesto discover the cause of the error.

Semantic Errors Logic or Meaning Errors Errors that indicate the logic used when coding the program

failed to solve the problem. Man bites dog.

You do not get error messages with logic errors. Your only clue to the existence of logic errors is the

production of wrong solutions.

Run-time Errors (Exceptions) Code does something illegal when it is run (hence runtime)

E.g., divide by zero

Syntax refers to the structure of a program and

the rules about that structure

Procedural


72/101

programming producedsignificantimprovements insoftware quality anddevelopment time

SoWhy are Programmers Now Using


73/101

SoWhy are Programmers Now UsingObject-Oriented Programming?

Increasing dependence on informationprocessing is creating a crisis

Volume of information is increasingfaster than the ability to create software

Programmers cannot generate softwareto keep pace with the potential of newhardware

Some Programming Issues are Not


74/101

g gAdequately Addressed by ProceduralProgramming

It is rarely possible to anticipate the design of a completedsystem before its actually implemented

Systems are works in progress

Development of GUIs is very complicated in traditionalprocedure-oriented programming languages

Sharing data across routines is difficult and error-prone

Focus of structured programming is on the modularity andprocedures

Data interactions are ignored Allowing modules to share all their data and interact freely

creates subroutines that are very dependent on each other--therefore, we dont have independent routines

So, Whats the Answer to theD t Sh i P bl ?


75/101

,Data Sharing Problem?

Modularize the data along with the procedures bygiving each subroutine its own local data that italone can read and write

INFORMATION

HIDING

Information Hiding Allows theP t W k ith M d l


76/101

Programmer to Work with Modules orProcedures Developed by Others at an

Abstract Level Abstraction

Internal details are hidden from the user

Data and procedures are not exposed toprocedures not needing to know them

Another Advantage of Object


77/101

Another Advantage of Object-Oriented Programming is

Reusability Building a house

Electrical system

Plumbing system

Heating/airconditioningsystem

Objects in Windows

Buttons Menus

Fields

ow roce ura rogramm ng oo s a aProblem


78/101

Problem

Procedures

Data acted upon by the procedures aremaintained separately from the procedures

Data assumes a secondary role!

Program

Procedure

Procedure Data

ow ec - r en e rogramm ngLooks at a Problem?


79/101

Looks at a Problem?

Objects

Data

Methods

Scope Methods surround

the data andprotect data from

other objects Encapsulation and

InformationHiding!

Data

Objects


80/101

j

Objects are things (nouns)

Objects have attributes (properties)Adjectives that describe an object

Objects have methods (behaviors)

Verbs that specify what the object can do Events are used to trigger behaviors

Objects interact with each other by passingmessages amongst themselves

Why Do We till Write ProceduralPrograms?


81/101

yPrograms?

Way of breaking a program into routines

Object-oriented programming works at ahigher level of abstraction than procedural

programming does After objects have been identified, methods

are designed using procedural techniques

We are concentrating on methods or

procedures


82/101

Common Business-OrientedLanguage (COBOL)


83/101

Sample Cobol program

Language (COBOL) COBOL:

The earliest (1959)high-level language

The most widelyused businesslanguage

A proven way to doaccounting,inventory, billing, and

payroll

Requiresprogrammers toexplain what the

program is doing at

Formula Translator (Fortran)


84/101

Sample Fortran program

Formula Translator(Fortran) Fortran:

Began in the 1950sIs suited toscientific,mathematical, and

engineeringapplications

Is used to solvecomplex equations

Features simplicity,economy, and easeof use

Ada


85/101

Sample Ada program

Ada

Ada:

Named afterAugusta Ada Byron

Incorporatesmodularprogramming

The requiredlanguage for theU.S. Defense

DepartmentSuitable for control

of real-timesystems (missiles)

Beginners All-Purpose SymbolicI t ti C d (BASIC)


86/101

Sample BASIC program

g p yInstruction Code (BASIC)

BASIC:

An easy-to-use language available on personalcomputers

Widely taught in schools as a beginners

programming language

Designed as an interpreted language

Visual Basic (VB)


87/101

Visual Basic (VB)

Visual Basic:Is widely used inprogram developmentpackages

Uses event-drivenprogramming

Enables theprogrammer to developan application by usingon-screen graphical userinterfaces

Sample Visual Basic

Sample Pascal programPascal


88/101

Sample Pascal program

Pascal:

Is named after Blaise Pascal

Encourages programmers to write well-structured

programs

Widely accepted as a teaching language

Has been updated to reflect new approaches to

programming

C


89/101

Sample C program

C C:

Was developed byAT&Ts Bell Labs in

the 1970s Combines high-

level programming

language withassembly language

Programmersmanipulate bits ofdata within a

processing unit

Difficult to learn andprogramming is time

consuming

Smalltalk


90/101

Sample Smalltalk program

Smalltalk:Developed in the 1970s by

Xerox Corp

100% pure object-

oriented programminglanguage

Not often chosen forsoftware development


91/101

C++ C++:

Incorporates object-oriented features

Is widely used for

professional programdevelopment

Sample C++ program

Java


92/101

Java

Java:Developed by Sun Microsystems

An object-oriented, high-level

programming language with a twistFirst true cross-platform

programming language

Gained acceptance faster than any

other programming languageA simplified version of C++


93/101

Java

Java, continued :

Java is designed to run on any computer platform

Java Virtual Machine enables cross-platformuse

Java applets or small programs are downloadedto computers through networks

Weaknesses include:The security risk in downloading applets

The speed in running the programs

Sample Java Program


94/101

p g

Web-Based Languages


95/101

Web Based Languages Markup languages:

Hypertext markup language (HTML) sets theattributes of text and objects within a Web page

Extensible markup language (XML) is used forsharing data and objects in a Web environment

Scripting languages:

VBScript is used to write short programs (scripts)that are embedded in Web pages

JavaScript is used to write scripts on Web pages

Visual Studio .NET:

Used forthe development of scripts andprograms that are accessible from the Web

The Programming Life Cycle


96/101

The Programming Life Cycle

Define the problem

Make or buy software?

Design the program by making an algorithm


Document the program

Compile and execute the program

Syntax and run time errors Test (debug) the program

Logic errors

Summary


97/101

Summary A programming language is an artificial language

consisting of a vocabulary and a set of rules Machine language is the lowest-level programming

language

Assembly language contains symbols for

programming instructions Third-generation (high-level) languages require

programmers to specify the procedures to be followed

Object-oriented languages combine procedures anddata

Summary continued


98/101

Summary, continued

The SDLCs six phases are:

Defining the program

Designing the program

Coding the program

Testing, debugging, and formalizing the program Implementing and maintaining the program

Top-down programming makes programs easier to debugand maintain

Debugging requires finding and correcting syntax errorsand logic errors

Flowcharts for the three constructs


99/101

Alternative ontrol tructureFlowcharts


100/101

Flowcharts Sequence

Selection Repetition (Looping)

Pseudocode! What is pseudocode?

P d d i b i ll h t E li h h d t l i ifi t k ithi ' l ith


101/101

Pseudocode is basically short, English phrases used to explain specific tasks within a program's algorithm.

Pseudocode should not include keywords in any specific computer languages.

Indentation can be used to show the logic in pseudocode as well.

Why is pseudocode necessary?

Writing pseudocode WILL save you time later during the construction & testing phase of a program'sdevelopment lets you think out the program before you code it.

How do I write pseudocode?

Consists mainly of executablestatements

Original Program Specification:Write a program that obtains two integer numbers from the user.

It will print out the sum of those numbers.

Variables required (names and types):int1: (integer) to store first integerint2: (integer) to store the second integersum: (integer) to store the sum of the numbers

Pseudocode:Prompt the user to enter the first integer int1Prompt the user to enter a second integer int2Compute the sum of the two user inputs sum = int1 + int2Display an output prompt that explains the answer

If you cant write it in pseudocode, you

wont be able to write it in C++!

02 Intro to Cpp

Documents

Transcript of 02 Intro to Cpp