Need help fixing my code to calculate the most efficient form of euro change to give a customer (greedy algorithm)

bill = 1 + (200-1) .* rand(1,1)

bill = round(bill,2)

pay = input("How much cash did the customer give you?")

change1 = pay-bill

%calculates the change the customer should recieve after handing you a certain amount of money

function[efficient_change] = change(change1)

initial amounts of each coin

one_cent = 0;

two_cents = 0;

five_cents = 0;

ten_cents = 0;

twenty_cents = 0;

fifty_cents = 0;

one_eurocoin = 0;

two_eurocoin = 0;

five_eurobill = 0

ten_eurobill = 0;

twenty_eurobill = 0;

fifty_eurobill = 0;

onehundred_eurobill = 0;

fivehundred_eurobill = 0;

change = [one_cent two_cent five_cents ten_cents twenty_cents fifty_cents one_eurocoin two_eurocoin five_eurobill ten_eurobill twenty_eurobill fifty_eurobill onehundred_eurobill fivehundred_eurobill];

change =[0 0 0 0 0 0 0 0 0 0 0 0 0 0]

while money>0

while money>=0

makes an infinte loop

if money >= 0.01

money = money - 0.01;

one_cent = one_cent + 1;

elseif money >= 0.02

money = money - 0.02;

two_cents = two_cents + 1;

elseif money >= 0.05

money = money - 0.05;

five_cents = five_cents + 1;

elseif money >= 0.10

money = money - 0.10;

ten_cents = ten_cents +1;

elseif money >= 0.20

money = money - 0.20;

twenty_cents = twenty_cents + 1;

elseif money >= 0.50

money = money - 0.50;

fifty_cents = fifty_cents + 1;

elseif money >= 1.00

money = money - 1.00;

one_eurocoin = one_eurocoin +1;

end

end

coins = [one_cent two_cent five_cents ten_cents twenty_cents fifty_cents one_eurocoin two_eurocoin];

bills = [five_eurobill ten_eurobill twenty_eurobill fifty_eurobill onehundred_eurobill fivehundred_eurobill]

disp("Give them back" (bills,coins))

end

end

%supposed to calulate the most efficient change in coins and billls (but not sure what to do)

Answer 1

[Govind KM]

Hi Nicky,

It seems to me that you are trying to calculate the change to be given to a customer, randomly generating the bill amount to be paid and taking the cash given by them as input.

A general structure you can follow for your function to calculate change efficiently without the need to use a while loop is:

function[efficient_change]=change(money)
    %Initialise the amount of each coin or bill using a single array of
    %size equal to the number of different denominations
    efficient_change=zeros(1,n);
    %Here n is the number of different denominations
    
    %Calculate the number of bills of each denomination needed using math,
    %going from higher to lower value. An example for the five euro bill is
    efficient_change(4)=floor(money/5);
    money=money-efficient_change(4)*5;
    %Assuming the five euro bill is 4th in the efficient_change array
end

Hope this is useful.