Question

用c语言编写：输入n的值，求1/2+1/4+1/8+......+1/n的值。

Answer 1

我就当你的n指的是项数了，n最大到30
#include<stdio.h>
main()
{
short n;long m;double s=0;
scanf("%d",&n);m=1<<n;
for(short i=n;i>1;i--)s+=1.0/(m>>=1);
printf("%.17f\n",s);
}

Answer 2

#include <stdio.h>
int main(void)
{
int n,i;
long m=1;
float s=0,t;
printf("输入n(n>0):\n");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
m=m*2;
t=1.0/m;
s=s+t;
}
printf("s=%f\n",s);
getchar();getchar();
}