Real World Vending Machine Feature: Reduce Coin Supply!

[nelsonic]

As the company owning/operating vending machines - that sell delicious healthy vegan snacks,
we need to ensure that we give the correct change when people pay with cash
so that we don't accidentally short-change people and upset them.

We need to account for the "supply" of coins in the machine being reduced each time change is given and not attempt to give coins which are unavailable in the machine.

• Create a function reduceCoinSupply that takes an array of "coins available" (coinsAvail) and an array of "coins given as change in the current transaction" (changeGiven) and returns an third array which is the coinsAvail minus the changeGiven.

Note: this is not "matrix math", it's simply removing elements from an array.

relates to #34 ... I don't want to simply switch to Tap from Tape without showing a valid use-case! 😉

[nelsonic]

Failing Test:

[nelsonic]

Function exists but result is null:

[nelsonic]

Passing: