import java.util.*;
public class Num39 {
public static double fn1(int n){
double sum=0,p;
n=2;
for(int i=1;i<=n/2;i++){
p=1/n;
sum=sum+p;
n=n+2;
}
return sum;
}
public static double fn2(int n){
double sum=0,p;
n=1;
for(int i=1;i<=(n+1)/2;i++){
p=1/n;
sum=sum+p;
n=n+2;
}
return sum;
}
public static void fn3(int n){
if(n%2==0)
{ System.out.println(fn1(n));
}
else
{ System.out.println(fn2(n));}
}
public static void main(String args[]){
int n;
Scanner sc=new Scanner(System.in);
System.out.println("输入整数n:");
n=sc.nextInt();
fn3(n);
}
}
出错了 帮忙找找