调和级数求和

1/1+1/2+1/3...+1/n~ln(n+1) +r,r是欧拉常数，r=0.5772156649.

#include<cstdio>#include<cstring>#include<cmath>#include<iostream>#include<algorithm>using namespace  std;int main(){    int i,n;    double s;    while(cin>>n){        if(n<=1000000){            s=0;            for(i=1;i<=n;i++) s+=1.0/i;        }        else{            s=0.5772156649+log(n+1.0);        }        printf("%.4lf\n",s);    }}