ch25-8.c

C语言程序设计上机指导与练习 冶金工业出版社 刘怀亮

#include <conio.h>
#include <math.h>
#include <stdio.h>

/*实现本程序有关迭代方法求方程问题的countValue()函数*/
float countValue()
{ 
   double x0,x1;
   x1=0.0;
   do{ x0=x1;
        x1=cos(x0);
    }while(fabs(x0-x1)>=0.000001);
   return(x1);
}

void writeDat()
{
   FILE *wf;
   wf=fopen("OUT.DAT","w");
   fprintf(wf,"%f\n",countValue());
   fclose(wf);
}

void main()
{
   printf("实根=%f\n",countValue());
   printf("%f\n",cos(countValue())-countValue());
   writeDat();
}