第十二周-牛顿迭代法求根

#include <stdio.h>
#include <math.h>
int main()
 {
  double solut(double ,double ,double ,double );
  double a,b,c,d;
  scanf("%lf%lf%lf%lf",&a,&b,&c,&d);
  printf("%.2f",solut(a,b,c,d));
  return 0;
 }
 double solut(double a,double b,double c,double d)
 {
    double x1=1,x0;
    double f(double a,double b,double c,double d,double x);
    double f_1(double a,double b,double c,double x);
    double y(double x);
    while(fabs(x1-x0)>=1e-5)
    {
    x0=x1;
    x1=x1-f(a,b,c,d,x1)/f_1(a,b,c,x1);
    //函数调用中的变量顺序弄错了
    }
    return x1;
 }
 //我错误地理解为f(x)和0的差表示精度。。。
double f(double a,double b,double c,double d,double x)
{
   return ((((a*x)+b)*x+c)*x+d);
}
double f_1(double a,double b,double c,double x)
{
    return ((3*a*x*+2*b)*x+c);
}
#include <stdio.h>
#include <math.h>
int main()