The program uses a for loop to iterate each year of the bank account interest.
Example:
> python bank_account.py
> This program calculates the future value of a 10-year investment.
> Enter the amount invested each year (for 100 dollars enter "100"): 100
> Enter the annual interest rate (for 1% enter ".01": .05
> Enter the number of years to compound (for 5 year input "5"): 10
> year 1: balance of $105, a gain of $105
> year 2: balance of $215, a gain of $110
> year 3: balance of $331, a gain of $115
> year 4: balance of $452, a gain of $121
> year 5: balance of $580, a gain of $127
> year 6: balance of $714, a gain of $134
> year 7: balance of $854, a gain of $140
> year 8: balance of $1002, a gain of $147
> year 9: balance of $1157, a gain of $155
> year 10: balance of $1320, a gain of $162