83！

83 date：2021.2.23

要点：
求绝对值函数：
fabs() 浮点型
abs() 整型

详细代码如下：

#include   <stdio.h>
#include   <math.h>
double fun(double  x)
{
    
      double  f, t;      int  n;
   f = 1.0 + x;
   t= x;
   n = 1;
   do {
    
    
      n++;
      t*=(-1.0)*x/n;
      f += t;
   }
    while(fabs(t) >=1e-6);
   return  f;
}
void main()
{
    
       double x, y;
   x=2.5;
   y = fun(x);
   printf("\nThe result is :\n");
   printf("x=%-12.6f y=%-12.6f\n", x, y);
}

要点：

详细代码如下：

#include  <math.h>
#include  <stdio.h>
double fun(double x)
{
    
     
	/*
		analyse:		
		……
	*/

	double s1 = 1.0, p = 1.0, sum = 0.0, s0, t =1.0;

	int n = 1;

	do{
    
    
		s0 = s1;
		sum += s0;
		t *= n;
		p *= (0.5-n+1)*x;
		s1 = p/t;
		n++;

	}while(fabs(s1-s0) >= 1e-6);

	return sum;
}
void main()
{
    
     int i;
  double x,s;
  FILE *out;
  printf("Input x: ");
  scanf("%lf",&x);
  s=fun(x);
  printf("s=%f\n ",s);
  /******************************/				 /*这里包含输出文件程序*/
  out=fopen("out.dat","w");
  for(i=20;i<30;i++)
    	fprintf(out,"%f\n",fun(i/100.0));
  fclose(out);
  /******************************/
}