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Multisets and Multimaps

I was trying to understand where multisets would be used as compared to multimaps and I

didnt find any straightforward answer. I found this simple explanation at StackOverflow:

multimap

y With ZIP code as a key, all people which have that ZIP code

y With account ID as key, all open orders of that person/account

y A dictionary, with per keyword various explanations

multiset

is in essence a map with a key and a integer count.

y The inventory of a shop, all products have their key and the amount still available is the value

y accumulated sales data of a shop, every time a product is sold the product id get's added to the

multiset thereby increasing the amount sold

As a result I created this example below. This is probably not the best of examples but I

didnt want to change it. The main problem below is that multimap's are not strictly speaking

required in the example below. I could have used a map. Multimap would be needed if there

was no quantity_ in the class and then I can add the products one by one. I could have then

used the count method to get the quantity.

Anyway, program as follows:

//Program tested on Microsoft Visual Studio 2008 - Zahid Ghadialy

//Simple example of multiset

#include

#include

#include

#include

#include

using namespace std;

class Product //Keeping this simple

{

public:

Product(string name, int code, int price) :

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name_(name), productCode_(code), price_(price)

{

quantity_= 10; //Lets fix this value for simplicity

}

bool availableForSale()

{

if(quantity_>0)

{

quantity_--;

return true;

}

return false;

}

string name_;

int productCode_;

int price_;

int quantity_;

private:

Product(); //Disabled the default constructor

};

void sellProduct(string name, multimap& inventory, multiset

&soldItems)

{

multimap::iterator it = inventory.find(name);if(it != inventory.end())

{

if ((*it->second).availableForSale())

{

soldItems.insert((*it->second).productCode_);

}

}

else

{

cout

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multimap::iterator it = inventory.begin();

for(it = inventory.begin(); it != inventory.end(); ++it)

{

int soldCount = soldItems.count((*it->second).productCode_);

cout

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soldItemsList(inventory, soldItems);

cout