property of jack wilson, cerritos college1 cis 103 - computer programming logic programming concepts...

Property of Jack Wilson, Cerritos College 1

CIS 103 - Computer Programming Logic

Programming Concepts Overview

prepared by Jack WilsonCerritos College

Programming Concepts Overview Property of Jack Wilson, Cerritos College2

Topics

1.1 Programs

1.2 Modules1.3 Algorithms1.4 Statements1.5 Syntax & Semantics1.6 Logic Planning Tools 1.7 Control Structures 1.8 Memory Concepts

1.9 Data Types


1.1 Programs

A program contains one or more modules.

Many languages require a module with a special name, such as "main" for a program to be created.

Programs are often also referred to as applications or more generally as software.

Program

module

module


1.2 Modules

A module is a collection of statements that perform a specific task within a program.

Module is a generic term. The most commonly used terms are listed below.

function C, C++, Python method Java


1.3 Algorithms

An algorithm is the name given to the logic that is developed and used to code the statements in a module.

Implementation of the algorithm in a module (function):

double square ( double number ){ return number * number;}

Algorithm to square a number:

1. get a number

2. multiply the number by itself

3. return this value


1.4 Statements

A statement is the name given to a high level language instruction.

Programs are written using a variety of different types of statements. Examples include: Declaration int count Assignment count = 0 Input get(number) Output put(“Grand Total is “ + total) Module Invocation printHeadings()


1.5 Syntax & Semantics

Syntax refers to the rules of a language that must be followed to construct a valid statement. Statements are constructed using the following components:

reserved words ( aka keywords ) identifiers operators literals punctuation symbols

Semantics refers to the meaning of a statement. It addresses the question "What does the statement do?“.


1.6 Control Structures

A control Structure determines the flow of execution for statements executing in a module.

There are 3 control structures that are used in all programming languages:

1. Sequence 2. Selection 3. Repetition (aka Iteration)



Sequence Structure

A sequence structure performs a single task without asking any questions or repeating anything. • declare a variable• assign a value to a variable• input a value• output a value• call a function• return a value from a function• stop program execution



Selection Structure

Asks a question (called a condition) and based on the answer ( true or false ) follows a path of execution.

In example 2, only one of the paths of execution would be followed.

The diamond symbol represents a condition that evaluates to true or false.

Example 1 – One path of execution

Example 2 – Two paths of execution

truefalse

false true

The rectangle

represents a structure.



Repetition Structure

Asks a question (called the condition) and based on the answer ( true or false ) executes a statement or exits the structure.

Continues to execute the statement as long as the condition evaluates to yes.

A repetition structure is often called a "loop".

Example 1: Pre-test loop

Example 2: Post-test loop

true

false

false

true

The rectangle represents a statement.

The diamond represents a condition.


1.7 Logic Planning Tools

Pseudocode Flowchart Hierarchy Chart Printer/Screen Spacing Chart File Description (record layout chart)


1.8 Memory Concepts

Memory is measured in bytes ( KB / MB / GB / TB )

A byte is 8 bits ( binary digits )

Every byte in RAM memory is assigned a unique address

Data types use one or more bytes to store information

integer – 4 bytes real number – 8 bytes


1.8 Memory Concepts

To avoid having to reference a specific location in memory to access a piece

of data, variable names are used instead of addresses. To use a variable in

a program, you must declare the variable by giving it a name and a data

type.

[ RAPTOR does not require us to do this ]

Examples:

int count boolean finished string name

When a program is executed, a symbol table ( think of it as a data dictionary

in memory ) is created that maps the name of a variable to the location in

memory where the data is being stored.


1.9 Data Types

Numeric integer numbers real numbers

Text a single character value a "string" of characters

Boolean True False

Programs work with data ( information stored in locations in memory ).There are many different categories of data.

Every language has specific keywords which are used to specify a data type. Not all data types are supported in all languages.

Here are some examples:

Language Numeric Text Boolean

Java intlongfloatdouble

charString

boolean

C++ intlongfloatdouble

charstring

bool


x.Xx Program Translation

Translators Assembler Compiler Interpreter

JIT compilation


Identifiers


Expressions and Statements


Object-Oriented Programming


Procedural Programming


Event-Driven Programming


Reserved Words


Operators

Mathematical (arithmetic) Relational (boolean) Logical


Operator Precedence and Associativity


File Input


File Output


Program Development


Making Decisions


Looping


Working with Strings


Arrays


Classes


Class Diagrams


Formatted Output

property of jack wilson, cerritos college1 cis 103 - computer programming logic programming concepts...

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