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DEPARTMENT OF MECHANICAL ENGINEERING

UNIVERSITY OF MORATUWA

CS2880

OBJECT ORIENTED PROGRAMMING USING C++

Manoj Ranaweera

Lecturer

Department of Mechanical Engineering

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EXAMPLE 02 - TEMPLATE FUNCTION

Define an overloaded function named Maximum to get

the maximum of 4 integers, 4 floating point numbers.

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int Max( int []);

float Max( float []);

void main()

{

int intVal[4];

float floatVal[4];

coutintVal[0];

cin>>intVal[1];

cin>>intVal[2];cin>>intVal[3];

coutfloatVal[0];

cin>>floatVal[1];

cin>>floatVal[2];

cin>>floatVal[3];

cout

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FUNCTIONTEMPLATES

Takes any type of input and returns any type

Templates are used when it is required to overload functionswhich differ only in data type

Example:

template

A TempFun( A a, C c) // if there is no return, just omit it

{

// statements

retunrn a;

}

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EXAMPLE

Repeat the above example using a function template

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{

A max;

max = number [0];

for ( int i = 1 ; i< 4 ; i++)

{

if(number[i] > max)

max = number [i];

}

return max;

}

void main(){

int intVal[4];

float floatVal[4];coutintVal[0];

cin>>intVal[1];

cin>>intVal[2];

cin>>intVal[3];

coutfloatVal[0];

cin>>floatVal[1];

cin>>floatVal[2];

cin>>floatVal[3];

cout

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USERDEFINEDDATATYPES

What are built-in data types?

What is a user defined data type?

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ENUMERATION

What is enumeration?

How to define an enumeration?

enum TypeName {SYMBOL_1 , SYMBOL_2, }

Here TypeNameis the name of the new data type

SYMBOL_1, SYMBOL_2 etc. are the values which the new

data type TypeNamecan accept

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English Meaning List, Record, Inventory

In C++, it is a collection of know symbols

with predefined values (or defaults)

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ENUMERATION

Key points

Unless otherwise defined, first element is assigned zero Unless otherwise defined, any element is given one incremented

value of previous element

current_element = previous_element +1

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enum Place {FIRST, SECOND, THIRD}

0 1 2

enum Place {FIRST =1 , SECOND, THIRD}

1 2 3

enum Place {FIRST =5, SECOND, THIRD =18}

5 6 18

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ARRAYSOMEPOINTSTONOTE

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enum defines only data

typesNOTvariables !!

enum Place {FIRST, SECOND, THIRD}

Defining variable of type Place

Place var_1;

Place var_2;

Variables var_1 and var_2 can hold

only FIRST, SECOND or THIRD only

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EXAMPLE 01

Write a program to get the marks of Mathematics subjects of 10

students along with their names. (Marks are given as integer valuesonly). Hold the marks and names in arrays. Define a function named

GetCredit which takes the mark of a student as an input parameter

and decide and returns the credit of the student based on the

following given criterion. Define an enumeration named Result

which can takes data A,B,C,D, and F only. Results must be printed on screen within main function after taking

all 10 marks

Criteria (Marks m)

(m>=75 grade A), (65

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IDENTIFIER ATTRIBUTES

Basic information provided by a variable definition

Name

Type (size in memory)

Value (optional)

Additional information provided Storage class

Scope

Linkage

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ENDNext Lecture

Pointers

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STORAGE CLASS

What it tells?

When and how long does the variable exist in memory

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Storage Class

Static Automatic

Created once

Data retains throughout the

programInitialized to zero automatically,

unless otherwise initialized

Initialized only once

Use the keyword static

Created whenever the block is

executed

Destroyed after executionNo data retention

No special keyword is needed

(a keyword called auto exist,

though rarely being used)

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SCOPE

Scope determines where the variable can be referenced

Scope categories

Functional scope

Ex: Labels have functional scope. (only labels have the true

functional scope. However, local variables in functions which are not

defined in any block within the function have the functional scope)

Block scope

Ex: anything lies within a block bounded by curly brackets { }

File scope

Ex: Global variables, function declarations etc

etc

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LINKAGE

It determines whether the variable is available only to the file

it is defined or to other files as well Use extern keywords to make it available to other files

extern must be used if the project has more than one source

files NOT header files

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