Python money denomination loop does not work on decimal-CodePudding

I am learning python and I what I need to achieve is to count how many denominations of 1000, 500, 200, 100, 50, 20, 10, 5, 1 , 0.25, 0.01 count base on my input data of 1575.78.This specific code bums me out.

def withdraw_money():
denoms = (1000, 500, 200, 100, 50, 20, 10,5,1,.25,0.01)
while True:
    try:
        withdraw = 1575.770
        break
    except Exception as e:
        print('Incorrect input: %s' % e)
    

print("Here is the bill breakdown for the amount input")
for d in denoms:
    count = withdraw // d
    print('P%i = %i' % (d, count))
    withdraw -= count * d
 

withdraw_money()

My current output is:

Here is the bill breakdown for the amount input

P1000 = 1
P500 = 1
P200 = 0
P100 = 0
P50 = 1
P20 = 1
P10 = 0
P5 = 1
P1 = 0
P0.25 = 3
P0.01 = 2

which is wrong because the P0.01 = 2 is suppose to be P0.01 =3.

However this code is correct when running whole numbers like 1500, or 20 but large number with decimal it get wrong on the 0.01 denomination count.

CodePudding user response：

After debugging the code, I found the error. Using round() solve the problem.

def withdraw_money():
    denoms = (1000, 500, 200, 100, 50, 20, 10,5,1,0.25,0.01)
    while True:
        try:
            withdraw = 1575.77
            break
        except Exception as e:
            print('Incorrect input: %s' % e)
        
    print("Here is the bill breakdown for the amount input")
    for i in range(len(denoms)):
        if denoms[i] != 0.01: count = withdraw // denoms[i]
        else: count = withdraw / denoms[i]
        print(f'P{denoms[i]} = {count:0.0f}')
        withdraw = round(withdraw % denoms[i],2)
     

withdraw_money()

CodePudding user response：

You can use f string here like below

def withdraw_money():
    denoms = (1000, 500, 200, 100, 50, 20, 10, 5, 1, .25, 0.01)
    while True:
        try:
            withdraw = 1575.770
            break
        except Exception as e:
            print('Incorrect input: %s' % e)

    print("Here is the bill breakdown for the amount input")
    for d in denoms:
        count = withdraw // d
        print(f'P{d} = {count:0.0f}')
        withdraw -= count * d


withdraw_money()

Output:

Here is the bill breakdown for the amount input
P1000 = 1
P500 = 1
P200 = 0
P100 = 0
P50 = 1
P20 = 1
P10 = 0
P5 = 1
P1 = 0
P0.25 = 3
P0.01 = 1