Add multiple data in a std::set using +=operator

hi

can anyone tel me how to insert multiple data at once in a std::set using an +=operator?

i've created this function to insert a product into a set, but i don't know how to use an +=operator :-(

Code:

void grocery::insertProducts()
{
	set <product> Prod;

	string typeP, detalP, idP;
	unsigned int costP;


	cout<<"\n Type: ";
	getline(cin,typeP);
	fflush(stdin);

	cout<<"\n Detailes: ";
	getline(cin,detalP);
	fflush(stdin);
	
	cout<<"\n Cost: ";
	cin>>costP;

	cout<<"\n Product ID: ";
	getline(cin,idP);

	product insertProd(typeP, detalP, costP, idP);

	Prod.insert(insertProd);
}

can anyone help?

Overload the += operator for grocery. Something like:

Code:

void grocery::operator+= (const product& p)
{
    mySet.insert(p);
}

(I'm not sure if this is good use for operator overloading. A function name conveys more information about what to expect from it.)

Note that in your existing code the set is local to the method and disappears when the function exists.

You can't use += to add to a set. You use insert instead, which you seem to already be doing.

A couple other comments about the code:

1. You created a set call Prod and insert a product into it. But that set is a local variable that is destroyed when the function ends, so you really did nothing. Shouldn't you be inserting into a member variable of the grocery class?
2. fflush(stdin); is bad and unnecessary. I'm not sure why you think you need it, but I'm pretty sure you don't. Remove it.
3. You call cin>>costP; and then call getline(cin,idP); just below it. If you use cin>> and getline together, you need to add a cin.ignore() after the cin>> call to ignore the trailing newline. This should only be done after cin>>, not after getline.

hey Anon

for the operator to work, i need to insert the code i used in my function ( void grocery::insertProducts(); ) to the new +=operator function ( void grocery:perator+= (const product& p); ), right?

Originally Posted by IndioDoido

hi
can anyone tel me how to insert multiple data at once in a std::set using an +=operator?

Use std::set<T>::insert( start, end ) where start is the first element you want to insert and end is the last element to insert (assuming they're in some kind of array or iterable container).

hi cpjust,
but i need to use a +=operator :-(

Do you need to use it on the set (which is not possible) or for your class?

If you want it for your class, then what do you want to add? I assume you want to add a product, but that means that the code that gets the data for the product from cin must be put somewhere else.

i have a class product with the elements for each product (price, type, etc...) and i need to create a simple program to insert, search, update and erase products from a set.

but i must use a +=operator to insert several products at the same time :-(

Please give more information, perhaps an entire paragraph. Or just answer the questions asked.

You cannot use += to insert into the standard library's set class.

What your assignment probably wants is to add an operator+= to the grocery class or some other class that holds multiple Products. It's up to you to tell us if that's true.

I'm going to try and translate the assignment requirements:

"The product table must support addictions of new products through a +=operator (supporting multiple addictions at once)."

Its not easy for me, explaining myself in a different language, sorry.

Ok, so that is referring to a "product table", not the standard library std::set class. That's the distinction I wanted to make.

I'm not sure how you can add multiple products at once. That doesn't make sense to me.

Do you have a class for your "product table"? Add an operator+= to that class. Use anon's code as an example.

Hope that makes sense.

ok, thanks for the help, i'm going to work on that later.

now i'm trying to find a product using .find(), but it doesn't work :-(

Code:

void grocery::findProduct()
{
	string id;

	cout<<"Product ID: ";
	cin>>id;

	set <product>::const_iterator it;

	if( Prod.find(id) == Prod.end() ) //set <product> Prod; is inside the grocery.h
		cout<<"not found\n";
	else cout<<"\nthe product type is: "<<it->getType() <<"\n";

	system("pause");

}

i know the product was inserted because after insertion, i view all products to be certain.

hi Daved!

thats correct, when i insert a product it has an ID, type, detail and cost.
i'm going to try that...

tnx again ;-)

I moved my post to your new thread... it's a new topic anyway so you can continue to discuss it there. Sorry for the confusion.

ok...
no problem ;-)