Exercise · Final Project · lesson 3 of 3

Exercise: generic warehouse

Write the class template template <typename Item> class Inventory, a warehouse that counts the units of each item. Keep the quantities in a std::map<Item, int>; add the fields yourself.

void add(const Item& item, int qty) puts qty units of item into the warehouse. bool take(const Item& item, int qty) takes them out and returns true. int count(const Item& item) const returns how many units of the item the warehouse holds.

after add("apple", 5) and add("apple", 3): count("apple") → 8
when count("pear") is 2: take("pear", 3) → false, and count("pear") stays 2
for an item that was never added: count("kiwi") → 0

Constraints: qty is positive, and the tests use std::string and int as Item. If there are fewer units than qty, take returns false and changes nothing, and count returns 0 for an unknown item.

inventory.cpp — cpp

cpp · 17 lines

#include <map>

template <typename Item>
class Inventory {
public:
    void add(const Item& item, int qty) {
    }

    bool take(const Item& item, int qty) {
        return false;
    }

    int count(const Item& item) const {
        return -1;
    }
};

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