COMP 102

Programming Fundamentals I

Presented by : Timture Choi

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Introduction to C++ C++ Extension of C Supports OO programming Free-format languageGeneral form Comment Include necessary header files “main()” function

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CommentsProvides explanatory notes

Purpose of the program/each function Usage of each variableAppear in green in VC++

1. Single line comments //

2. Multiple line comments /* … */

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Compiler DirectivesAppear in blue in VC++Import the required library in programPre-defined #include <xxx> E.g. <iostream>, <math>User-defined #include “xxx.h”

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“main()” FunctionStart of the programVariables/constant declaration Must be declared before used Identifier

Name for variables/constant/function Should not be a keyword Case sensitive Start with letter

Statements Deal with user input/output Specific calculation

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Programming StyleFree-format language Increase writability

How easily a language can be used to write programs Decrease readability

Measures how easy it can be understoodNote: Write comments for both variables and

functions Use meaningful variable names Only one statement for each line

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DeclarationsAllocation Reserves memory to store constants and

variablesDeallocation Releases storage of constants and variables

from memoryBinding Associates the constants/variables with

memory location

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DeclarationsConstant Cannot be changed throughout the

program Syntax:

const <type> <identifier> = <expression>;

const: keyword E.g.

const double pi=3.14, gravity=9.8;

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DeclarationsVariable Can be changed during program

execution Note: will not be initialized automatically

Better to initialize when declared Syntax:

<type> <identifier>; <type> <identifier>, <identifier>; <type> <identifier> = <expression>;

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Data Typevoid

no value and operationint

Integer 32 bits (4 bytes)

Float Floating point 32 bits (4 bytes)

Double 64 bits (8 bytes)

char Character

bool Either true/false

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Data TypeNote: Precision Data size

Depend on design/compiler of the languageBytes/BitsOverflow/UnderflowAffect program size

Data range Signed/Unsigned

Signed bit

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SUMMARYBy the end of this lab, you should be able to: Understand the general form of a program

Comments Compiler directives “main()” function Keyword and identifier

Defined and Initialized Constants Variables

With appropriate data types

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