#include #include #include int substr(char dst[], char src[], int start, int len

#include<stdio.h>
#include<stdlib.h>
double print_s(int a)
{
double p1[50],p2[50],Sn[50];
int i = 0;
p1[0] = 2;
p2[0] = 1;
Sn[0] = p1[0] / p2[0];
for (i = 1; i < a; i++)
{
p1[i] = p1[i - 1] + p2[i - 1];
p2[i] = p1[i] - p2[i - 1];
Sn[i] = Sn[i - 1] + (p1[i] / p2[i]);
}
return (Sn[a - 1]);
}
int main()
{
int a;
printf("请输入您要打印这个分数序列前几项和：");
scanf("%d",&a);
printf("本序列前%d项和Sn=%2.5f\n",a,print_s(a));
system("pause");
return 0;
}