Write a program that reads in positive floating-point numbers from standard input and prints their geometric and harmonic means. The geometric mean of n positive numbers x1, x2, ..., xn is (x1 - x2 - ...  xn)1/n. The harmonic mean is n / (1/x1 + 1/x2 + ... + 1/xn). Hint : For the geometric mean, consider taking logarithms to avoid overflow.