Object-Oriented Programming

thoreldan SG

always use a accessor instead...

declaring instance variable as public is very bad programming.

anyway.. private and protected can mean different thing

ndmmxiaomayi SG

I stand corrected. I've always used public. Embarassed

thoreldan SG

Embarassed

LatecomerX SG

Me curious here, why is it a bad programming practice to declare such vars as public?

And to mayi: in the future, please spell my username as "LatecomerX', not with the "C" capitalized. A big "C" there looks...kinda weird. Embarassed

ndmmxiaomayi SG

See wrongly. Embarassed

eagle SG

I vaguely remember that it is because we do not want any other things anyhow access that data accidentally or something like that

gigabyte14 SG

java Laughing

i got B, and i don't know how i got a B

eagle SG

C++ I got A+
But I returned 80% of the things le

ndmmxiaomayi SG

That piece of code is not Java, although concepts are the same.

gigabyte14 SG

paiseh la Embarassed

LatecomerX SG

Oh. But use public accessor to get the var also can have accidents de ma.

thoreldan SG

it's about information hiding and encapsulation

think of the class as a blackbox
you dont need to know what is inside(instance variables)...you just need to know what it does(methods provided)

(i'm using java terminology....c++ might have slight variations)

Xcert SG

Still on the subject of C++,anyone knows how to pass an object into a function as an input parameter?

assuming a class named COMPUTER is already defined...
something like the following(which obviously can't work Laughing )...

one-niner SG

where are your header files for these 2 classes ? Will need to take a look at them to be sure.

But as suggested by others on the thread.You will need to use accessor and mutator methods to explicty set and obtain the values you need.

Remember Strong Cohesion Loose Coupling.

Program with Performance in mind =)

I think you come from a java background right ? hence the different syntax and thought it can be achieved

Xcert SG

not really...I only know a bit of everything...started with Turbo C++...then VB6 for a project...then VC++(also project but foundation damn weak)...then the internet things like java,jsp,asp,applet,apache,IIS,PHP,mySQL,Oracle,etc...also know a bit of uP programming...now learning VC++ from scratch...at the same time need to come up with a windows device driver.I am so screwed. Rolling Eyes

and ya...I guess U can say that my knowledge is pretty mixed up. Embarassed

I understand the meaning of accessor...but what is a mutator method?function overloading?

one-niner SG

accesor methods are used to obtain the values of object states. Another term used is getter method

Mutator methods are used to set/initalize values of object states.Another term used is setter method

Function Overloading.One of the beauties of the object oriented paradigm.

gived this 2 method signature

performCalculation(int days,double basic salary,String position)
performCalculation(int days,double basic salary)

They have the same method name,except they differ in method signature. These are used as means by a programmer to expose interfaces of different input parameters to callers on a basic level due to different business requirements.In computer science speak, its called Polymorphism.

There is another form of polymorphism called method overiding.This is usually perform at the inherited class level. 1 good example will be the toString() method in the J2SE API.

By default when you type this.toString(); information abt the instantiated object is displayed to the standard output.usually in a derived class, you will overwrite the method by declaring the same method name & signature. But within the method body, you will write your own code to display what is deem fit for your object as determined by the functional specs determined by your application architect/designer.

A quick getup to C++ will be the HowTo code series from Deitel & Deitel is a gd way to learn CPP to bring your langauge proficency up to speed.

Last used Visual CPP and they are good for the MFC, but i used them back in 2001. Been a Java/J2EE guy since Uni days till now thought.But i did have to write some core libraries on my previous project in C++ and that gave me a gd headstart in basic CPP and STL.

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