牛顿迭代算法实现-C语言

牛顿迭代

用于一元高次方程求解
$$例如：y=x\ast x-5=0$$

#include <stdio.h>
#include <math.h>
double F(double x, double n) {
	return (x * x - n);
}

double f(double x) {
	return 2 * x;
}

double newton(double (*F)(double, double), double (*f)(double), double n) {
	double x = n / 2;
#define EPSL 1e-6
	while (fabs(F(x, n)) > EPSL) {
		x -= F(x, n) / f(x);
	}
#undef EPSL
	return x;
}

int main() {
	double n;
	while(~scanf("%lf", &n)) {
		printf("%g\n", newton(F, f, n));
	}
	return 0;
}