logic formulation. what is logic formulation? logicformulationlogicformulation the process of coming...

Logic Logic FormulatioFormulatio

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What is Logic What is Logic Formulation?Formulation?

The process of coming out with the The process of coming out with the basic steps to implement a basic steps to implement a procedure in computer procedure in computer programming. This is usually programming. This is usually resorted to when having top-down resorted to when having top-down design. Flowcharts and pseudo design. Flowcharts and pseudo codes are the two of most common codes are the two of most common output of the exercise.output of the exercise.

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Bringing the steps as required Bringing the steps as required by the task in PROPER ORDER by the task in PROPER ORDER so that when it is executed so that when it is executed procedurally the desired result procedurally the desired result is achieved according to the is achieved according to the required output specification.required output specification.

- - Nilo M. PadreNilo M. Padre

What is Logic Formulation? ….

Basic Control StructuresBasic Control Structures

(logical constructs that specify (logical constructs that specify how instructions in a program how instructions in a program are to be executed) are to be executed)

SequenceSequenceSelectionSelectionRepetitionRepetitionUnconditional JumpUnconditional Jump

SequenceSequenceInstructions are designed to be Instructions are designed to be

executed (performed by the executed (performed by the computer) in the order they are computer) in the order they are written (i.e., one after another). written (i.e., one after another). This control structure provides the This control structure provides the building block for computer building block for computer programs. It is used to show a programs. It is used to show a single action or one action followed single action or one action followed in order (sequentially) by another. in order (sequentially) by another. ActionsActions can be can be inputsinputs, , processesprocesses, , or or outputsoutputs..

ExampleExample

Go to the phoneGo to the phoneDial the pizza placeDial the pizza placeOrder the pizzaOrder the pizzaHang upHang up

Sequence StructureSequence Structure

SelectionSelection (conditional, branch, or (conditional, branch, or decision)decision)

The program branches off to different The program branches off to different instructions depending on whether a instructions depending on whether a condition is met; or, one of several condition is met; or, one of several blocks of program code is executed blocks of program code is executed based on a test for some condition. It is based on a test for some condition. It is used to tell the program which action to used to tell the program which action to take, based on a certain condition. When take, based on a certain condition. When a condition is evaluated, its result is a condition is evaluated, its result is either true or false. If the result is true, either true or false. If the result is true, one action is performed; if the result is one action is performed; if the result is false, a different action is performed.false, a different action is performed.

ExampleExample

Open your walletOpen your walletIf you have enough money,If you have enough money,

THEN Go to the phone.THEN Go to the phone.Dial the pizza place.Dial the pizza place.Order the pizza.Order the pizza.Hang up.Hang up.

ELSE Forget the whole thing. ELSE Forget the whole thing.

Selection StructureSelection Structure

Single SelectionSingle Selection

T

F

Double SelectionDouble Selection

TF

Selection Structure ...

Multiple SelectionMultiple Selection

T

F

T

F

T

F

Selection Structure ...

RepetitionRepetition (looping or (looping or iteration)iteration)

The program repeats the same The program repeats the same instructions over and over. It is instructions over and over. It is used when a set of actions is to used when a set of actions is to be performed repeatedly.be performed repeatedly.

ExampleExample

DO gobble down pizzaDO gobble down pizzaWHILE there is still pizza.WHILE there is still pizza.

OrOrDO gobble down pizzaDO gobble down pizzaUNTIL none remains.UNTIL none remains.

RepetitionRepetition

While StructureWhile Structure

T

F

For StructureFor Structure

T

F

Repetition Structure ...

Do/While StructureDo/While Structure

Repetition Structure ...

T

F

Unconditional BranchUnconditional Branch

The program jumps from one The program jumps from one place to another. Structured place to another. Structured programming forbids this programming forbids this structure.structure.

A part of SDLC’s implementation A part of SDLC’s implementation phase and provides an organized phase and provides an organized plan for breaking down the task of plan for breaking down the task of program development into program development into manageable chunks, each of which manageable chunks, each of which must be successfully completed must be successfully completed before moving on to the next phase.before moving on to the next phase.

An outline of each of the steps used An outline of each of the steps used to build software applications. to build software applications.

Program Development Life Program Development Life CycleCycle

1. Analyze: Define the 1. Analyze: Define the problem.problem.

Be sure you understand what the Be sure you understand what the program should do.program should do.

What the output should be – that is, What the output should be – that is, exactly what the task should exactly what the task should produce.produce.

Identify the data, or input, necessary Identify the data, or input, necessary to obtain the desired output.to obtain the desired output.

Determine how to process the input Determine how to process the input to obtain the desired output – that is, to obtain the desired output – that is, determine what formulas or ways of determine what formulas or ways of doing things can be used to obtain doing things can be used to obtain the output.the output.

2. Design: Plan the solution to 2. Design: Plan the solution to the problem.the problem.

Develop the Develop the algorithmalgorithm (a (a logical sequence of precise logical sequence of precise steps that solve the problem). steps that solve the problem). Every detail, including obvious Every detail, including obvious steps, should appear in the steps, should appear in the algorithm. algorithm.

Translate the algorithm into a logic Translate the algorithm into a logic plan using any of the popular plan using any of the popular methods – flowcharts, pseudocode, methods – flowcharts, pseudocode, top-down charts. These design top-down charts. These design tools help the programmer break a tools help the programmer break a problem into a sequence of small problem into a sequence of small tasks the computer can perform to tasks the computer can perform to solve the problem. Planning also solve the problem. Planning also involves using representative data involves using representative data to test the logic of the algorithm by to test the logic of the algorithm by hand to ensure that it is correct.hand to ensure that it is correct.

3. Choose the interface: Select 3. Choose the interface: Select the objects (text boxes, the objects (text boxes, command buttons etc.)command buttons etc.)

Determine how the input will be Determine how the input will be obtained and how the output will be obtained and how the output will be displayed. Then create objects to displayed. Then create objects to receive the input and display the receive the input and display the output. Also, create appropriate output. Also, create appropriate command buttons and menus to allow command buttons and menus to allow the user to control the program.the user to control the program.

This step is used with Windows Application This step is used with Windows Application but not with Console Application.but not with Console Application.

4. Code: Translate the 4. Code: Translate the algorithm/flowchart/pseudalgorithm/flowchart/pseudocode into a programming ocode into a programming language.language.

During this stage, the program is written During this stage, the program is written in a particular language (e.g., Visual in a particular language (e.g., Visual Basic, C, Java) and entered into the Basic, C, Java) and entered into the computer. The programmer/coder uses computer. The programmer/coder uses the algorithm/flowchart/pseudocode the algorithm/flowchart/pseudocode devised in Step 2 along with a devised in Step 2 along with a knowledge of the programming knowledge of the programming language, say, Visual Basic.language, say, Visual Basic.

5. Test and debug. Locate and 5. Test and debug. Locate and remove any errors in the remove any errors in the

programprogram..As the program is typed, some code editors As the program is typed, some code editors

point out certain types of program errors. point out certain types of program errors. Other types will detected by when the Other types will detected by when the program is compiled ( or interpreted) program is compiled ( or interpreted) and/or executed; however, many errors due and/or executed; however, many errors due to typing mistakes, flaws in the algorithm, to typing mistakes, flaws in the algorithm, or incorrect usages of the language rules or incorrect usages of the language rules can be uncovered and corrected only by can be uncovered and corrected only by careful detective work. An example of such careful detective work. An example of such an error would be using addition when an error would be using addition when multiplication was the proper operation.multiplication was the proper operation.

6. 6. Complete the Complete the documentation: Organize documentation: Organize all the material that all the material that describes the program.describes the program.

Documentation is intended to allow Documentation is intended to allow another person, or the programmer another person, or the programmer at a later date, to understand the at a later date, to understand the program. Internal documentation program. Internal documentation consists of statements in the consists of statements in the program that are not executed, but program that are not executed, but point out the purposes of various point out the purposes of various parts of the program. parts of the program.

Documentation might also Documentation might also consist of a detailed consist of a detailed description of what the description of what the program does and how to use program does and how to use the program (for instance, the program (for instance, what type of input is what type of input is expected). expected).

Documentation…

For commercial programs, For commercial programs, documentation includes an documentation includes an instruction manual and on-line help. instruction manual and on-line help. Other types of documentation are Other types of documentation are the flowchart, pseudocode, and top-the flowchart, pseudocode, and top-down chart that were used to down chart that were used to construct the program. Although construct the program. Although documentation is listed as the last documentation is listed as the last step in the program development step in the program development cycle, it should take place as the cycle, it should take place as the program is being coded.program is being coded.

Documentation…

Flowcharting SymbolsFlowcharting Symbols

Some Application Flowcharting Some Application Flowcharting SymbolsSymbols

Direct Access File

Card File

Computer Program

Document (such as hard copy from a computer system

Some Application Flowcharting Symbols…

Display

Multidocument

Manual Input

Preparation

Manual Operation


Punched Tape

Collate

Sort

Extract


Merge

Sequential Access Storage

Magnetic Disk

Direct Access Storage

Application FlowchartingApplication FlowchartingThe purpose of an application The purpose of an application

flowchart is to use symbols to give a flowchart is to use symbols to give a general picture of what functions the general picture of what functions the computer system should perform.computer system should perform.

It reveals how many program are to It reveals how many program are to be written, what reports or documents be written, what reports or documents are to be produced, and the form and are to be produced, and the form and source of the input data.source of the input data.

It gives an overall picture of the It gives an overall picture of the application.application.

Program Flowcharting Program Flowcharting SymbolsSymbols

Documentation…

Example ProblemExample Problem

Suppose you are asked to Suppose you are asked to determine the number of determine the number of stamps to place on an stamps to place on an envelop with the rule or envelop with the rule or policy that one stamp will be policy that one stamp will be used for every five sheets of used for every five sheets of paper.paper.

Problem AnalysisProblem Analysis

Program DesignProgram Design

Documentation…

Choosing the InterfaceChoosing the InterfaceForm LayoutForm Layout

Properties TableProperties Table

Properties Table…

Coding the ProgramCoding the Program

Coding the Program…

ProblemProblem

Given a street number of a one-way Given a street number of a one-way in New York, decide the direction of in New York, decide the direction of the street, either eastbound or the street, either eastbound or westbound. Even-numbered streets westbound. Even-numbered streets run eastbound.run eastbound.

Thank you for listening!

ArraysArrays

ArrayArray

An ordered set of values associated with An ordered set of values associated with a single variable name. –a single variable name. –Shelly, Cashman, Dorin, Shelly, Cashman, Dorin, QuasneyQuasney

A list of data items that all have the A list of data items that all have the same type and the same name. - same type and the same name. - FerrelFerrel

A data structure whose elements are A data structure whose elements are accessed by means of index positions. – accessed by means of index positions. – Lambert & OsborneLambert & Osborne

A collection of a fixed number of A collection of a fixed number of variables of the same data type or a list variables of the same data type or a list (or table) of variables of the type. -(or table) of variables of the type. - GoldsteinGoldstein

Declaring an ArrayDeclaring an Array

Arrays are declared in a variable Arrays are declared in a variable declaration section.declaration section.

General Syntax in C/C++General Syntax in C/C++

component type component type arraynamearrayname[[sizeNsizeN]…]…[[size1size1];];

DimensionDimension

The number of subscripts required to The number of subscripts required to describe an array.describe an array.

The The subscriptsubscript or or indexindex is the item’s is the item’s position in an array. It is an integer position in an array. It is an integer enclosed within the brackets (square enclosed within the brackets (square or rounded).or rounded).

Declaration SyntaxesDeclaration SyntaxesFor One-DimensionalFor One-Dimensional

type type array_namearray_name[[sizesize];];

For Two-DimensionalFor Two-Dimensional

type type array_namearray_name[[rowsrows][][columnscolumns];];

For Three-DimensionalFor Three-Dimensional

type type array_namearray_name[[pagespages][][rowsrows]][[columnscolumns];];

ExamplesExamples

double double Department[7];Department[7];

The component of this array are:The component of this array are:

Department[0]Department[0]Department[1]Department[1]Department[2]Department[2]Department[3]Department[3]Department[4]Department[4]Department[5]Department[5]Department[6]Department[6]

char char Sign[25];Sign[25];

The components of this array are:The components of this array are:Sign[0]Sign[0]Sign[1]Sign[1]Sign[2]Sign[2]......Sign[25]Sign[25]

typedef enum {Red, Green, Yellow} typedef enum {Red, Green, Yellow} TrafficLight;TrafficLight;

TrafficLight Traffic[4];TrafficLight Traffic[4];

The components are:The components are:

Traffic[0]Traffic[0]




Assigning A Value to an ArrayAssigning A Value to an Array

The components of an array may be The components of an array may be assigned values just like any other assigned values just like any other variables. variables.

Examples:Examples:

FirstVisit[1] = Fri;FirstVisit[1] = Fri;

Traffic[3]=Red;Traffic[3]=Red;

Department[5]=290.12;Department[5]=290.12;

Sign[24]=‘*’;Sign[24]=‘*’;

Initializing an ArrayInitializing an Array

SyntaxSyntax

type-specifier type-specifier array_namearray_name[[sizeNsizeN]…[]…[size1size1] ] = { = { value-listvalue-list } }

ExamplesExamples

Int num[7] = {1,2,3,4,5,6,7}Int num[7] = {1,2,3,4,5,6,7}

char str[8]=“Laughter”;char str[8]=“Laughter”;

which is the same aswhich is the same as

Char Char str[8]={‘L’,’a’,’u’,’g’,’h’,’t’,’e’,’r’}str[8]={‘L’,’a’,’u’,’g’,’h’,’t’,’e’,’r’}

int sqrs[7][2]= {int sqrs[7][2]= {

1,1,1,1,

2,4,2,4,

3,9,3,9,

4,16,4,16,

5,25,5,25,

6,36,6,36,

7,497,49

};};

Unsized-Array InitializationUnsized-Array Initializationchar err1[12]=“read error\n”;char err1[12]=“read error\n”;char err2[13]=“write error\n”;char err2[13]=“write error\n”;char err3[18]=“cannot open file\n”;char err3[18]=“cannot open file\n”;

which is the same as,which is the same as,char err1[]=“read error\n”;char err1[]=“read error\n”;char err2[]=“write error\n”;char err2[]=“write error\n”;char err3[]=“cannot open file\n”;char err3[]=“cannot open file\n”;

int sqrs[][2]= {int sqrs[][2]= {1,1,1,1,2,4,2,4,3,9,3,9,4,16,4,16,5,25,5,25,6,36,6,36,7,497,49

};};

LogicLogic

The grammar of correct thinking and The grammar of correct thinking and reasoning. reasoning.

Two Elements:Two Elements:To think correctly and; To think correctly and; To reason out correctly.To reason out correctly.

If one of the elements would be missing, If one of the elements would be missing, then no logic can be derived from. then no logic can be derived from.

– – Nilo M. PadreNilo M. Padre

FormulationFormulation An act or the product of formulating.An act or the product of formulating.- Merriam Webster Merriam Webster

(http://www.merriam-webster.com/dic(http://www.merriam-webster.com/dictionary/formulation)tionary/formulation)

●● The act of creating something by The act of creating something by thinking thinking

- The Free Dictionary The Free Dictionary (http://www.thefreedictionary.com/for(http://www.thefreedictionary.com/formulation)mulation)

logic formulation. what is logic formulation? logicformulationlogicformulation the process of coming...

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