Object-Oriented Programming
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I vaguely remember that it is because we do not want any other things anyhow access that data accidentally or something like thatOriginally posted by LatecomerX: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.
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java
i got B, and i don't know how i got a B -
C++ I got A+Originally posted by gigabyte14:java
i got B, and i don't know how i got a B
But I returned 80% of the things le -
That piece of code is not Java, although concepts are the same.Originally posted by gigabyte14:java
i got B, and i don't know how i got a B -
paiseh laOriginally posted by ndmmxiaomayi:That piece of code is not Java, although concepts are the same. -
Oh. But use public accessor to get the var also can have accidents de ma.Originally posted by eagle:I vaguely remember that it is because we do not want any other things anyhow access that data accidentally or something like that -
it's about information hiding and encapsulationOriginally posted by LatecomerX:Oh. But use public accessor to get the var also can have accidents de ma.
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) -
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 )...code:
#include
void somefunction(object comOBJ);
void main()
{
COMPUTER comOBJ;
somefunction(comOBJ);
}
void somefunction(object comOBJ)
{
//some functionality
} -
Originally posted by Xcert: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 )...code:
#include
void somefunction(object comOBJ);
void main()
{
COMPUTER comOBJ;
somefunction(comOBJ);
}
void somefunction(object comOBJ)
{
//some functionality
}code:
#include
void somefunction(object comOBJ);
void main()
{
COMPUTER comOBJ;
somefunction(comOBJ);
}
void somefunction(COMPUTER comOBJ)
{
//some functionality
} -
where are your header files for these 2 classes ? Will need to take a look at them to be sure.Originally posted by Xcert:code:
#include
#include
#include
#include
class employee
{
private:
int nSalary;
char name[80];
int nDept;
public:
void SetSalary(int);
void PrintSalary();
void SetName(char *aString);
protected:
};//end class employee
void employee::SetSalary(int s)
{
nSalary=s;
}//end void employee::SetSalary
void employee:: PrintSalary()
{
cout<<"nSalary of "<}//end void employee:: PrintSalary()
void employee::SetName(char *aString)
{
if(strlen(aString)<=79)
{
strcpy(name,aString);
}
else
{
strcpy(name, "Default" );
}
}//end void employee::SetName(char *aString)
class manager:public employee //Derived class
{
private:
int nOffice;
public:
void SetOffice(int);
void PrintOffice();
protected:
};//end class manager:public employee
void manager::SetOffice(int o)
{
nOffice=o;
}//end void manager::SetOffice(int o)
void manager:: PrintOffice()
{
cout<<"nOffice of "<}//end void manager:: PrintOffice()
anyone knows how can I print out the name of the manager in the last line.
Employee is the base class,manager is the derived class.
manager.name is obviously not correct.
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 -
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.Originally posted by one-niner: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
and ya...I guess U can say that my knowledge is pretty mixed up.
I understand the meaning of accessor...but what is a mutator method?function overloading? -
accesor methods are used to obtain the values of object states. Another term used is getter methodOriginally posted by Xcert: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.
and ya...I guess U can say that my knowledge is pretty mixed up.
I understand the meaning of accessor...but what is a mutator method?function overloading?
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.