Question

Programming language: PYTHON
Prompt: You will be creating a program to show final investment amounts from a principal using simple or compound interest. First, get a principal amount from the user. Next, ask the user if simple or compound interest should be used. If the user types in anything other than these options, ask again until a correct option is chosen. Ask the user to type in the interest rate as a percentage from 0 to 100%. Finally, ask the user for the number of years of this investment. If simple interest is chosen: For each year, show the user the year number and total amount of interest earned to date. At the end, show the user the principal, the length of the investment, the type of interest and at what percentage, and the total final amount (i.e., principal plus total interest). If compound interest is chosen: For each year, show the user the year number and new principal. At the end, show the user the original principal, the length of the investment, the type of interest and at what percentage, and the final principal. The program only needs to run once per execution.
Key concepts and resources from class :

• While

• External resources and prior knowledge

Assumptions, checks, or procedures:

1. The user should be able to type “s” (lowercase, no quotes) for simple interest and “c” (lower case, no quotes) for compound interest. Anything other than “s” or “c” should be considered an invalid choice. Please see samples below.

2. The interest rate as a percentage (when the user types it in) must be a number between 0.0 and 100.0. For example, an interest rate of 4.5% would be entered as 4.5.

3. You will not be using any econ or finance formulas to calculate simple or compound interest. Instead, you will be doing the calculations “manually”.

4. You can assume that time is finite (the number of years entered by the user), the interest rate does not change over time, and interest is calculated once per year. You can consider any total amounts you show to be “end of year” amounts.

5. Decimal values are allowed. Round decimals in outputs to the nearest hundredth (i.e., same as you would see at a bank).

6. You will need to add dollar and percent signs to your output.

7. You can assume that inputs for principal, interest rate, and year will be valid. Inputs for year will not contain decimals. How to break down this prompt I’m going to heavily paraphrase your econ and finance classes (and we can make use of some assumptions) in describing the types of interest. Simple interest is calculated only on the principal and then summed yearly per the prompt. Compound interest is calculated on the new principal each year. Once you understand those differences, it’s just a matter of using while and other concepts to do that in code.

This is the code i have so far...this is the error i am getting : "Traceback (most recent call last): File "main.py", line 18, in while (i <= years): Type error: '<' not supported between instances of 'str'

principal = input("enter the principal amount:\t")

s = input("1. s for simple interest\n 2. c for compound interest\n enter your choice:\t")

while(s!='s' and s!='c'):

s = raw_input("1. s for simple interest\n2. c for compound interest\nenter your choice:\t")

if(s=='s'):

years = input("enter number of years:\t")

rateofinterest = input("enter rate of interest:\t")

i = 1

while(i<=years):

interest = (principal*i*rateofinterest)/100

amount = interest + principal

print("at the end of {} year interest:\t{} interest type: simple interest amount:\t{}".format(i,interest,amount))

i = i + 1

if(s=='c'):

years = input("enter number of years:\t")

rateofinterest = input("enter rate of interest:\t")

i = 1 while(i <= years):

interest = (principal*i*rateofinterest)/100

amount = interest + principal

print("at the end of {} year interest:\t{} interest type: compound interest amount:\t{}".format(i,interest,amount))

i = i + 1

principal = principal + interest

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

The main error in your code was the way you were trying to read values. The input() method returns a string value, not a numeric type. So principal=input(….) will read the principal value as a string and not floating point. If you need to read as float value, you should use float(input()) instead of input(), the same applies for int(). There were many other errors too. Fixed everything

#code

# the input() returns a string, not a numeric type
#if you need to input a floating point value, you should use float(input())
#if you need to input a integer value, you should use int(input())

#getting principal as a float value
principal = float(input("enter the principal amount:\t"))

#getting choice as string
s = input("1. s for simple interest\n2. c for compound interest\nenter your choice:\t")

#loops until a valid choice is made
while(s!='s' and s!='c'):
    s = input("1. s for simple interest\n2. c for compound interest\nenter your choice:\t")

if(s=='s'):
    #getting years as int and rate of interest as float
    years = int(input("enter number of years:\t"))
    rateofinterest = float(input("enter rate of interest:\t"))
    i = 1
    while(i<=years):
        interest = (principal*i*rateofinterest)/100
        amount = interest + principal
        #displaying year and interest earned. here {:.2f} will round the
        #decimal values into 2 decimal places and then display
        print("at the end of {} year interest earned:\t${:.2f}".format(i,interest))
        i = i + 1
    #displaying principal, length, type , interest rate and final amount
    print('principal: ${:.2f}, length of investment: {} years, type: simple interest'.format(principal,years),end=' ')
    print('interest rate: {:.2f}%, total final amount: ${:.2f}'.format(rateofinterest,amount))
if(s=='c'):
    years = float(input("enter number of years:\t"))
    rateofinterest = float(input("enter rate of interest:\t"))
    #finding starting principal
    current_principal=principal
    #finding the rate in which each time the interest is compounded in a year
    compound_interest_rate=(rateofinterest/12)/100
    i = 1
    while(i <= years):
        n=1
        #loops for 12 times (months in a year)
        while n<=12:
            #finding interest
            interest = current_principal * compound_interest_rate
            #updating principal
            current_principal = current_principal + interest
            n+=1
        #displaying principal at the end of year
        print("at the end of {} year principal amount:\t${:.2f}".format(i,current_principal))
        i = i + 1
    #displaying original principal, duration, interest rate and final principal
    print('original principal: ${:.2f}, length of investment: {} years, type: compound interest'.format(principal, years), end=' ')
    print('interest rate: {:.2f}%, total principal amount: ${:.2f}'.format(rateofinterest, current_principal))

#output

enter the principal amount:         125000

1. s for simple interest

2. c for compound interest

enter your choice:            c

enter number of years:   5

enter rate of interest:     7.25

at the end of 1 year principal amount:     $134369.79

at the end of 2 year principal amount:     $144441.92

at the end of 3 year principal amount:     $155269.04

at the end of 4 year principal amount:     $166907.74

at the end of 5 year principal amount:     $179418.86

original principal: $125000.00, length of investment: 5.0 years, type: compound interest interest rate: 7.25%, total principal amount: $179418.86