Write a program that finds the zero of a function between two limits. The program can assume that there is a single well defined root and that the function does not have any local maxima or minima between the limits. The calling sequence could look like:-
external test_func ! function with a single arg
logical fail
real test_func, x_lo, x_hi, x_root
call find_root( test_func, x_lo, x_hi, x_root, fail )
The driver program calls this function with limits supplied by the user.