Searching within an abstract data type (ADT)

[deanfamily11]

I have an ADT and I'd like to search for certain items in it. How can I
accomplish this?

[Jacques Labuschagne]

deanfamily11 wrote:

I have an ADT and I'd like to search for certain items in it. How can I
accomplish this?

Be more specific. Does the object have a container you need to search
through? Or are you talking about using reflection to find/invoke a
particular function? Or are you trying to use assumptions about the
object layout to find certain data members?

Jacques.

[deanfamily11]

Ok, here's an example and please note this is supposed to be an array of
class objects or variables, also note that >> indicates that those are
variable of that item in the array:
book[1]

title
author
price book[2]title
author
price

book[3]
....

In this case, I'd like to be able to search through all of the items for a
given title supplied by the user.

"Jacques Labuschagne" <ja*****@clawsh rimp.com> wrote in message
news:Mt******** *************@n ews.xtra.co.nz. .. deanfamily11 wrote:

I have an ADT and I'd like to search for certain items in it. How can I
accomplish this?

Be more specific. Does the object have a container you need to search
through? Or are you talking about using reflection to find/invoke a
particular function? Or are you trying to use assumptions about the object
layout to find certain data members?

Jacques.

[Jacques Labuschagne]

deanfamily11 wrote:

Ok, here's an example and please note this is supposed to be an array of
class objects or variables, also note that >> indicates that those are
variable of that item in the array:
book[1]

title
author
price
book[2]
title
author
price

book[3]
...

In this case, I'd like to be able to search through all of the items for a
given title supplied by the user.

OK, sounds simple so far. So what's the public interface of the Book
object? Something like this?

class Book{
private:
...
public:
const string& getTitle() const;
...
};

If so, then the solution is to step through the array and check the
value of Book::getTitle( ) for every element:

for (int i = 0; i < array_size; ++i){
if (array[i].getTitle() == user_title){
cout << "Found it!\n";
break;
}
}

Is there something wrong with this solution?

Jacques.

[deanfamily]

Your suggestion I think works, but I need to know how to define getBook in
the area to define the class.

"Jacques Labuschagne" <ja*****@clawsh rimp.com> wrote in message
news:BP******** *************@n ews.xtra.co.nz. ..

deanfamily11 wrote:

Ok, here's an example and please note this is supposed to be an array of
class objects or variables, also note that >> indicates that those are
variable of that item in the array:
book[1]

title
author
price

book[2]

title
author
price

book[3]
...

In this case, I'd like to be able to search through all of the items for
a given title supplied by the user.

OK, sounds simple so far. So what's the public interface of the Book
object? Something like this?

class Book{
private:
...
public:
const string& getTitle() const;
...
};

If so, then the solution is to step through the array and check the value
of Book::getTitle( ) for every element:

for (int i = 0; i < array_size; ++i){
if (array[i].getTitle() == user_title){
cout << "Found it!\n";
break;
}
}

Is there something wrong with this solution?

Jacques.

[Jacques Labuschagne]

deanfamily wrote:

Your suggestion I think works, but I need to know how to define getBook in
the area to define the class.

Why don't you post the code of your ADT so we have some context?

Jacques.

[deanfamily]

Ok, here it is for your reference, and also I need to do the search in ISBN
number:

class bookType
{
public:
//this part is for the book title
string printTitle() const;
void setTitle(string );
void checkTitle(stri ng);

//this part is for the number of copies
int showNumCopies() const;
void setCopies(int);
void updateCopies(in t);
int printNumCopies( ) const;

//this part is for the publisher
string showPublisher() const;
void setPublisher(st ring);
void updatePublisher (string);
string printPublisher( ) const;

//this part is for the ISBN
string showISBN() const;
void setISBN(string) ;
void updateISBN(stri ng);
string printISBN() const;

//this part is for the price
double showPrice() const;
void setPrice(double );
void updatePrice(dou ble);
double printPrice() const;

//this part is for the authors
string showAuthors() const;
void setAuthors(stri ng, int);
void updateAuthors(s tring, int);
string printAuthors() const;

private:
string title;
string publisher;
string isbn;
double price;
int numInStock;
string authors[4];
};

string bookType::print Title() const
{
return title;
}

void bookType::setTi tle(string titleName)
{
title = titleName;
}

void bookType::check Title(string newTitle)
{
if(newTitle == title)
cout << "That title already exists." << endl;
}

int bookType::showN umCopies() const
{
return numInStock;
}

void bookType::setCo pies(int copiesIn)
{
numInStock = copiesIn;
}

void bookType::updat eCopies(int newNum)
{
numInStock = newNum;
}

int bookType::print NumCopies() const
{
return numInStock;
}

string bookType::showP ublisher() const
{
return publisher;
}

void bookType::setPu blisher(string publish)
{
publisher = publish;
}

void bookType::updat ePublisher(stri ng newPub)
{
publisher = newPub;
}

string bookType::print Publisher() const
{
return publisher;
}

string bookType::showI SBN() const
{
return isbn;
}

void bookType::setIS BN(string isbnIn)
{
isbn = isbnIn;
}

void bookType::updat eISBN(string newIsbn)
{
isbn = newIsbn;
}

string bookType::print ISBN() const
{
return isbn;
}

double bookType::showP rice() const
{
return price;
}

void bookType::setPr ice(double priceIn)
{
price = priceIn;
}

void bookType::updat ePrice(double newPrice)
{
price = newPrice;
}

double bookType::print Price() const
{
return price;
}

string bookType::showA uthors() const
{
return authors[0];
return authors[1];
return authors[2];
return authors[3];
}

void bookType::setAu thors(string authorIn, int authNum)
{
authors[authNum] = authorIn;
}

void bookType::updat eAuthors(string setAuthor, int authNum)
{
authors[authNum] = setAuthor;
}

string bookType::print Authors() const
{
return authors[0];
return authors[1];
return authors[2];
return authors[3];
}
"Jacques Labuschagne" <ja*****@clawsh rimp.com> wrote in message
news:OG******** *************@n ews.xtra.co.nz. ..

deanfamily wrote:

Your suggestion I think works, but I need to know how to define getBook
in the area to define the class.

Why don't you post the code of your ADT so we have some context?

Jacques.

[John Harrison]

deanfamily wrote:

Ok, here it is for your reference, and also I need to do the search in ISBN
number:
OK that seems easy enough. See below

class bookType
{
public:
//this part is for the book title
string printTitle() const;
See the function you have called printTitle? It doesn't print anything
so it is badly named. In fact it is almost exactly the function getTitle
that Jacques imagined.

You could rewrite Jacques code like following

for (int i = 0; i < array_size; ++i){
if (array[i].printTitle() == user_title){
cout << "Found it!\n";
break;
}
}

No do you see how sily the name printTitle is? The above code works but
the name is confusing. So use Jacques' solution but rename the function
to getTitle, you will have to rename it everywhere that you are using it.

You have similar confusion all over the place. Look at this
void setCopies(int);
void updateCopies(in t);
void bookType::setCo pies(int copiesIn)
{
numInStock = copiesIn;
}

void bookType::updat eCopies(int newNum)
{
numInStock = newNum;
}
The functions setCopies and updateCopies are *exactly* the same. Why did
you feel the need to have two functions. Just get rid of one of them.

The same problems with many others, they are either duplicates or have
inappropriate names.

string bookType::print Authors() const
{
return authors[0];
return authors[1];
return authors[2];
return authors[3];
}

This just doesn't work, it will only return the first author (and again
it won't print anything) the three following return statements will be
ignored.

When I see these sort of naming problem I know the programmer is
confused. You shoul name a function after what it does, not how you use
it. getTitle because you the function get the title from the book, not
printTitle because you happed to use the function to print then title.

Assuming this is homework you will definitely lose marks for
inappropriate names for your functions, and also for having duplicate
functions.

john

[deanfamily]

The problem that I am mainly having with the code:

for (int i = 0; i < array_size; ++i){
if (array[i].printTitle() == user_title){
cout << "Found it!\n";
break;
is that == is for integers and it won't compile as a result. The
"user_title " and "printTitle " parts are strings. How do you change the code
so that it can be used for strings?

"John Harrison" <jo************ *@hotmail.com> wrote in message
news:wf******** *********@newsf e6-win.ntli.net... deanfamily wrote:

Ok, here it is for your reference, and also I need to do the search in
ISBN number:

OK that seems easy enough. See below

class bookType
{
public:
//this part is for the book title
string printTitle() const;

See the function you have called printTitle? It doesn't print anything so
it is badly named. In fact it is almost exactly the function getTitle that
Jacques imagined.

You could rewrite Jacques code like following

for (int i = 0; i < array_size; ++i){
if (array[i].printTitle() == user_title){
cout << "Found it!\n";
break;
}
}

No do you see how sily the name printTitle is? The above code works but
the name is confusing. So use Jacques' solution but rename the function to
getTitle, you will have to rename it everywhere that you are using it.

You have similar confusion all over the place. Look at this

void setCopies(int);
void updateCopies(in t);

void bookType::setCo pies(int copiesIn)
{
numInStock = copiesIn;
}

void bookType::updat eCopies(int newNum)
{
numInStock = newNum;
}

The functions setCopies and updateCopies are *exactly* the same. Why did
you feel the need to have two functions. Just get rid of one of them.

The same problems with many others, they are either duplicates or have
inappropriate names.

string bookType::print Authors() const
{
return authors[0];
return authors[1];
return authors[2];
return authors[3];
}

This just doesn't work, it will only return the first author (and again it
won't print anything) the three following return statements will be
ignored.

When I see these sort of naming problem I know the programmer is confused.
You shoul name a function after what it does, not how you use it. getTitle
because you the function get the title from the book, not printTitle
because you happed to use the function to print then title.

Assuming this is homework you will definitely lose marks for inappropriate
names for your functions, and also for having duplicate functions.

john

[Alf P. Steinbach]

* deanfamily:

[top- and middle-posting]

Please stop top-posting and middle-posting in this group.

Thanks.

- Alf
PS: Please also try the suggestions you've been given before protesting that
they won't work.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
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