C++
Do not use any global variables.
The presentValue function must have the following signature:
double presentValue(double futureValue, double interestRate, int numberYears)
Create multiple functions to find the present value.
The formula used needs the future value (F) and annual interest rate (r) and the number of years (n) the money will sit in the account, unchanged. You will be calculating the present value (P).
P = F / ( (1 + r) ^ n)
In the above expression the value (1 + r) needs to be raised to the nth power. Assume that ^ is the power function and x^2 is x to the 2nd power (x squared)
You must have functions to read in the future value, the annual interest rate, and the number of years. That would be three different functions. Give these functions meaningful names. Note that the order of the values will be future value, annual interest rate, and number of years.
In all cases you need to return any valid value back to the calling function.
For all three functions you will write out to cout as prompt for an input value. You will read in that value from cin. If the value is invalid (zero or negative) you need to display an error message and reread the value (with another prompt). You need to do this in a loop and continue looping until a valid value has been entered. Only the number of years can be an int value. The rest should be of type double.
Here are the prompts for the three values you need to read in:
Enter future value Enter annual interest rate Enter number of years
Note that the interest rate will be a number such as 10 or 12.5. These are to be read in as percentages (10% and 12.5%). You will need to divide these values by 100 to convert them into the values needed in the function (.1 and .125 for the above values). This conversion needs to be done before you call the presentValue function (see below). If you do the conversion in the presentValue function your program will fail the unit tests, so do the conversion
before
you call the calculate function.
Here are the error messages you need to display if the values are negative:
The future value must be greater than zero The annual interest rate must be greater than zero The number of years must be greater than zero
You will also need a function called presentValue with the following signature:
double presentValue(double futureValue, double interestRate, int numberYears)
The display function
You also need a function that displays the present value, future value, interest rate, and number of years. The function needs to display the interest rate as %, so .05 would display as 5.000%. Give your display function a meaningful name. You will be passing a number of values to this function.
Here is the sample output for a present value of $69,046.56, a future value of $100,000, an interest rate of 2.5% and a number of years of 15,
Present value: $69046.56 Future value: $100000.00 Annual interest rate: 2.500% Years: 15
Note that the present value and future value have three digits of precision to the right of the decimal point but the interest rate only has one digit to the right of the decimal point.
The main function will be the driver for your program.
Your program will only be processing one set of valid values for future value, annual interest rate and number of years.
Get the values for these by calling the read functions you created above.
Once you have the values you need to call your presentValue. Using the result from the presentValue and the input values you read in with your read functions you need to call your display function (written above) to display the values.
The main function will be the driver for your program. All of the non-main functions are called from main.