I have to implement a simple infinite sum which estimates the value of PI. The more iterations of the infinite sum, the more accurate the value of PI. Using the equation PI=4x(1-1/3+1/5-1/7+1/9-1/11+1/13-....)

.The details of the program are as follows:

1. The program must have a small menu for the purpose of user

interaction. The menu will contain the following choices:

1. Exit the program

2. Set how many digits past the decimal point are to be calculated

3. Calculate the value of Pi

(this part works for me)

2. I have to figure out how to determine when a digit is valid. (probably

by converting the floating point value of PI to a string and

checking for how many iterations the value of a digit is

unchanged.) Any valid algorithm to determine a valid digit is fine;

here is my code so far