/************************************************************************
*功能：计算序列  1.0 + 1.0/2.0 + 1.0/3.0 + 1.0/4.0 + ....                     
*              1.0 - 1.0/2.0 + 1.0/3.0 - 1.0/4.0 + ....            
*                具体计算到某一次由用户指定                             
************************************************************************/ 

#include<stdio.h>
 
 float sum1(int n);
 float sum2(int n);
 void show(float,float,int);
 int main(void)
 {
     int n = 0;
     float sum_1 = 0.0, sum_2 = 0.0;
     
     printf("how many times you want to add:(0--1000000)");
     while(scanf("%d",&n) == 1 && n > 0&& n < 1000000)
     {     
         sum_1 = sum1(n);
         sum_2 = sum2(n);
         show(sum_1,sum_2,n);
         printf("input next value(0--1000),q to quit:");
     }
     
     return 0;
 } 
 
 float sum1(int n)
 {
     float sum = 0.0;
    int i = 0;
    for(i = 1; i <= n; i++)
    {
        sum = sum + 1.0/(float)i;        
    } 
    return sum;
     
 }
 
 float sum2(int n)
 {    
     int i = 0,t = 1;
     float sum = 0.0;
     for(i = 1; i <= n; i++)
     {
         
        sum = sum + t * 1.0/(float)i;
        t = -t;
         
     }
     return sum;
     
 }
 void show(float sum_1, float sum_2, int n)
 {
     printf("sum_1 = %f\n",sum_1);
    printf("sum_2 = %f\n",sum_2);
    
 }