编程计算s=1-1/2+1/3-1/4+1/5-1/6+…+1/n
#include<stdio.h>#include<math.h>int main(void){int a,n;double sum=0;scanf("%d",&n);for(a=1;a<=n;a++){sum = sum+pow(-1,a+1)*(1.0/a);}printf("%f\n",sum);return 0;
}