Hi,
You can simply understand this rewriting your one method like here...
*public* *void* setFruitName(String fruitName)
{
*this*.fruitName = fruitName;
}
Now you might have to write "this" keyword to assign value to fruitName.
(declared as "*private* String fruitName;")
So "this" refers to the Instance.
- Hiran.
On Wed, Sep 30, 2009 at 1:07 AM, Rodrigo Dias <[email protected]>wrote:
> Hi Kat,
> I remember how much time it took me to understand the concept of variable
> class and when to use "this"... but its quite fundamental that you do so,
> here it is:
>
> A class has methods (functions).
> Inside the methods, you can define variables that can only be seen inside
> those methods. Other methods with variables with the same name will not be
> conflicting because they cannot see eachother.
> But there is a way of having variables that see eachother and that are
> "above" the methods. Those are the class variables. They are in the scope of
> the whole class (and probably to extended classes if you set them public)
> and they are prefixed with the word "this." .
> so:
>
>
> *public* *void* setFruitName(String temp)
>
> {
> *this*.fruitName = temp;-------------> heres a class variable that can be
> called from within any method and will be refering to the same one. In this
> case you are setting it to have the value of temp
>
> }
>
> *public* String getFruitName()
>
> {
> *return* fruitName;---------> this one is a simple method variable and
> exists only inside this method. You probably want to "return this.fruitName"
> instead. I wonder if this one isn't coughing an error of an undeclared
> variable....
>
> }
>
> Hope that makes sense!
>
> Rodrigo.
>
> 2009/9/29 kat Owens <[email protected]>
>
> Hi all,
>>
>> I am trying to understand when to use the "this" keyword.
>>
>> The following is my code : inside the setFruitName whether I use
>>
>> this.fruitName = temp;
>>
>> or fruitName = temp;
>>
>> both seem to work. why is that ?
>>
>> Thank You,
>>
>> Kat
>>
>>
>>
>> * *
>>
>> *package*
>> foodpackage.fruitpackage;
>>
>> *
>>
>> *
>>
>> *
>>
>> public
>> * *class* Food{
>>
>> *private* String fruitName;
>>
>> *private* *double* fruitPrice;
>>
>> *private* *double* *memberPrice*;
>>
>> *private* *double* salePrice;
>>
>> *private* *boolean* *isMember*;
>>
>> *private* *int* *FriutsBought*;
>>
>> *public* *void* setFruitName(String temp)
>>
>> {
>>
>> *this*.fruitName = temp;
>>
>> }
>>
>> *public* String getFruitName()
>>
>> {
>>
>> *return* fruitName;
>>
>> }
>>
>> *public* *void* setFruitPrice(*double* fruitPrice)
>>
>> {
>>
>> *this*.fruitPrice = fruitPrice;
>>
>> }
>>
>> *public* *double* getFruitPrice()
>>
>> {
>>
>> *return* fruitPrice;
>>
>> }
>>
>> *public* *void* setSalePrice( *double* fruitPrice)
>>
>> {
>>
>> *if* (*this*.isMember = *true*)
>>
>> *this*.salePrice = fruitPrice/2;
>>
>> *else*
>>
>> *this*.salePrice = fruitPrice;
>>
>> }
>>
>> *public* *double* getSalePrice()
>>
>> {
>>
>> *return* salePrice;
>>
>> }
>>
>> *public* *void* setIsMember (*boolean* isMember)
>>
>> {
>>
>> *this*.isMember = *true*;
>>
>> }
>>
>> *public* *static* *void* main (String[] args){
>>
>> Food apples =
>> *new* Food();
>>
>> apples.setFruitName(
>> "APPLES");
>>
>> apples.setFruitPrice(0.50);
>>
>> apples.setSalePrice(apples.getFruitPrice());
>>
>> System.
>> *out*.println(" The fruit name is " + apples.getFruitName());
>>
>> System.
>> *out*.println(" The fruit name is " + apples.getFruitPrice());
>>
>> apples.setIsMember(
>> *true*);
>>
>> System.
>> *out*.println(" The fruit name is " + apples.getSalePrice());
>>
>> apples.setIsMember(
>> *false*);
>>
>> System.
>> *out*.println(" The fruit name is " + apples.getSalePrice());
>>
>> Food oranges =
>> *new* Food();
>>
>> oranges.setFruitName(
>> "ORANGES");
>>
>> System.
>> *out*.println(" The fruit name is " + oranges.getFruitName());
>>
>> }
>>
>>
>>
>>
>>
>
> >
>
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