求f(n)=1+1/2+1/3+1/4+...+1/n
package hello1;
import java.util.Scanner;
public class fenshusum {
public static void main(String [] args)
{
Scanner in =new Scanner(System.in);
int n= in.nextInt();
double sum=0.0;
for(int i=1;i<=n;i++)
{
sum=sum+1.0/i;
}
System.out.println(sum);
// System.out.println("%.2f",sum);//取两位小数
}
}
求f(n)=1-1/2+1/3-1/4+1/5-1/6...+1/n
package hello1;
import java.util.Scanner;
public class fenshusum {
public static void main(String [] args)
{
Scanner in =new Scanner(System.in);
int n= in.nextInt();
double sum=0.0;
int sign=1;
for(int i=1;i<=n;i++)
{
sum+=sign*1.0/i;
sign = -sign;
}
System.out.println(sum);
// System.out.println("%.2f",sum);//取两位小数
}
}