原题：编写一个子程序NewTon（float x0，float eps，float x1）。它的功能是用牛顿迭代法求f（x）=x*x*x-2x*x+4x+1在x=0附近的一个实根。若迭代成功，则返回费0值；否则，返回0。-original title : the preparation of a subroutine NewTon (x0 float, float eps, float x1). Its function is to use Newton's iterative method for f (x) = x * x * x-2x 4x * x 1 x = 0 in the vicinity of a real roots. If successful iteration, the returned value fees 0; Otherwise, the return 0.