C语言函数数列题求解

函数fun()是根据正整数n，求下面数列的和 s=1+1/22+1/333+.+1/nn.nn
当输入n=5，s=1.04870057 ,注意:部分源程序给出如下。
请勿改动main函数和其他函数中的任何内容,仅在函数fun的注释语句之间填入所编写的若干语句。

#include<stdio.h>
#include<stdlib.h>
double fun(int n)
{
/Begin/

/*End*/

}
int main()
{
FILE *in,*out;
int n,i;
double s;
scanf("%d",&n);
s=fun(n);
printf("%.8lf\n",s);

in=fopen("in96.dat","r");
out=fopen("out96.dat","w");
while(!feof(in))
{
    fscanf(in,"%d",&n);
    fprintf(out,"%.8lf\n",fun(n));
}
fclose(in);
fclose(out);
   system("pause");
return 0;

}

供参考：

#include<stdio.h>
#include<stdlib.h>
double fun(int n)
{
    /*Begin*/
    int i ,k ,t;
    double s = 0;
    for (i=1 ;i <= n; i++)
    {
        k = i;t = 0;
        while (k--) t = t * 10 + i;
        s+=1.0/t;
    }
    return s;
    /*End*/
}
int main()
{
    FILE *in,*out;
    int n,i;
    double s;
    scanf("%d",&n);
    s=fun(n);
    printf("%.8lf\n",s);

    in=fopen("in96.dat","r");
    out=fopen("out96.dat","w");
    while(!feof(in))
    {
         fscanf(in,"%d",&n);
         fprintf(out,"%.8lf\n",fun(n));
    }
    fclose(in);
    fclose(out);
    system("pause");
    return 0;
}