#include "stdio.h" #include "math.h"

main() {double tsum=0.0; int n=1,k,a,sum,j=-1,d=1; printf("Please input n:"); scanf("%d",&a); sum=3; for(k=2;n<a;n++) {k=k*2; sum=sum+k;} printf("\n%d",sum);

for(;d<=(int)(sqrt(sum));d++) {j=-j; tsum=tsum+j*(1/(d)); } printf("\n%f",tsum);

}

想问问为甚么tsum的值不变啊？？按道理来说应该是1-(1/2)+(1/3)-(1/4)……(-1)^(k+1)*(1/k)啊

啊呀，原来我前面知识的基础还不够牢靠啊。谢谢指点。