Fixed Point Iteration or Successive Substitution

It is an Open Numerical method on finding the roots of a function. It plots the given function to help the user decide what initial guess to make. It would also ask for a lower and upper bound and evaluate if a root is available between that interval. The initial guess, as made by the user, must be between the lower and upper bounds. The user also has an option to choose between %relative error or number of iterations as the termination criterion.