intro-to-programming | Instructional materials for a one day intro | Learning library

I've already addressed most of my points in the comments, but I will recap: You are trying to solve a problem using a method called recursive solving, in this case using the bisection method.

The steps are as follows:

1. start with an initial guess you chose 0.5
2. Perform your calculations in a loop and iterate the initial guess, in this case you must account for the following:
3. Maximum number of steps before failure, remember we can always add 2 values and divide by 2, your result will tend to 0.999999.. otherwise
4. A certain tolerance, if your step size is not small enough 25% of 1 M is 250 000 and you might never hit that number exactly, that' why you make a tolerance interval, for example: anything between 250 000 and 251 000 --> break loop, show result.
5. Your if statements for changing low and high to adjust guess are correct, but you forget to re-initialize savings to 0 which means savings was going to infinity.

Now that's all said, here's a working version of your code: