Gross Store

10 Points

dictionaries

Instructions

A friend of yours has an old wholesale store called Gross Store.

The name comes from the quantity of the item that the store sell: it's all in gross unit.

Your friend asked you to implement a point of sale (POS) system for his store.

First, you want to build a prototype for it.

In your prototype, your system will only record the quantity.

Your friend gave you a list of measurements to help you:

Unit	Score
quarter_of_a_dozen	3
half_of_a_dozen	6
dozen	12
small_gross	120
gross	144
great_gross	1728

1. Store the unit of measurement in your program

In order to use the measurement, you need to store the measurement in your program.

let units = units();
// Felt252Dictionary with entries like { 'dozen': 12 }

2. Create a new customer bill

You need to implement a function that create a new (empty) bill for the customer.

let bill = new_bill();
// Empty Felt252Dictionary

3. Add an item to the customer bill

To implement this, you'll need to:

Return false if the given unit is not in the units map.
Otherwise add the item to the customer bill, indexed by the item name, then return true.
If the item is already present in the bill, increase its quantity by the amount that belongs to the provided unit.

let bill = new_bill();
let units = units();
let ok = add_item(bill, units, 'carrot', 'dozen');
println!(ok);
// Output: true (since dozen is a valid unit)

Note that the returned value is type bool.

4. Remove an item from the customer bill

To implement this, you'll need to:

Return false if the given item is not in the bill. An item is considered to not be in the bill if its quantity is 0.
Return false if the given unit is not in the units map.
Return false if the new quantity would be less than 0.
If the new quantity is 0, the item is considered removed from the bill, so you can return true.
Otherwise, reduce the quantity of the item and return true.

let bill = new_bill();
let units = units();
let ok = remove_item(bill, units, 'carrot', 'dozen');
println!(ok);
// Output: false (because there are no carrots in the bill)

Note that the returned value is type bool.

5. Return the quantity of a specific item that is in the customer bill

let mut bill: Felt252Dict<u32> = Default::default();
bill.insert('carrot', 12);
bill.insert('grapes', 3);
let qty = get_item(bill, 'carrot');
println!(qty);
// Output: 12

Note that the returned value is type u32.

cairo

Gross Store

10 Points

dictionaries

Instructions

A friend of yours has an old wholesale store called Gross Store.

The name comes from the quantity of the item that the store sell: it's all in gross unit.

Your friend asked you to implement a point of sale (POS) system for his store.

First, you want to build a prototype for it.

In your prototype, your system will only record the quantity.

Your friend gave you a list of measurements to help you:

Unit	Score
quarter_of_a_dozen	3
half_of_a_dozen	6
dozen	12
small_gross	120
gross	144
great_gross	1728

1. Store the unit of measurement in your program

In order to use the measurement, you need to store the measurement in your program.

let units = units();
// Felt252Dictionary with entries like { 'dozen': 12 }

2. Create a new customer bill

You need to implement a function that create a new (empty) bill for the customer.

let bill = new_bill();
// Empty Felt252Dictionary

3. Add an item to the customer bill

To implement this, you'll need to:

Return false if the given unit is not in the units map.
Otherwise add the item to the customer bill, indexed by the item name, then return true.
If the item is already present in the bill, increase its quantity by the amount that belongs to the provided unit.

let bill = new_bill();
let units = units();
let ok = add_item(bill, units, 'carrot', 'dozen');
println!(ok);
// Output: true (since dozen is a valid unit)

Note that the returned value is type bool.

4. Remove an item from the customer bill

To implement this, you'll need to:

Return false if the given item is not in the bill. An item is considered to not be in the bill if its quantity is 0.
Return false if the given unit is not in the units map.
Return false if the new quantity would be less than 0.
If the new quantity is 0, the item is considered removed from the bill, so you can return true.
Otherwise, reduce the quantity of the item and return true.

let bill = new_bill();
let units = units();
let ok = remove_item(bill, units, 'carrot', 'dozen');
println!(ok);
// Output: false (because there are no carrots in the bill)

Note that the returned value is type bool.

5. Return the quantity of a specific item that is in the customer bill

let mut bill: Felt252Dict<u32> = Default::default();
bill.insert('carrot', 12);
bill.insert('grapes', 3);
let qty = get_item(bill, 'carrot');
println!(qty);
// Output: 12

Note that the returned value is type u32.

cairo

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