有规律的数列求和

参考代码:

#include <stdio.h>

#include <stdlib.h>

float sum_dev(float fenzi,float fenmu,int n,float s){

if(n == 0) {

return s;

}

return sum_dev(fenzi+fenmu,fenzi,n-1,s + fenzi / fenmu);

}

int main(void){

int n;

float s;

scanf("%d",&n);

s = sum_dev(2.0,1.0,n,0);

printf("%.2f\n",s);

return 0;

}