Question

用C语言 n为奇数 请编写程序完成求和：s=1-1/3+1/5-1/7......+1/n 求s

Answer 1

#include <stdio.h>
#include <math.h>
void main()
{ int sign=1,n;
printf("input n=");
scanf("%d,&n);
float i=1,temp=1,s=0;
while(i<=n)
{s=s+temp;
i=i+2;
sign=-sign;
temp=sign/i;
}
printf("s=%8.6f\n",s);
}

Answer 2

#include<stdio.h>
int main (void)
{
printf("please give an odd number: ");
int n;
while(1)
if(scanf("%d", &n) != 1 || n < 0 || n % 2 != 1)
printf("wrong number!Try again: ");
else
break;
double sum = 0.0;
int i;
for(i = 1; i <= n; i+=2)
if(i % 4 == 1)
sum += 1 / (double)i;
else
sum -= 1 / (double)i;
printf("when n = %d, sum = %f\n", n, sum);
return 0;
}