根据经纬度计算两点球面距离

#include <iostream>
#include <cmath>


using namespace std;


double EARTH_RADIUS = 6378.137;//地球半径
double PI=3.1415926535;


double rad(double d){
   return d * PI / 180.0;
}


double round(double d){
  return floor(d + 0.5);
}


double get_distance(double lat1, double lng1, double lat2, double lng2)
{
   double radLat1 = rad(lat1);
   double radLat2 = rad(lat2);
   double a = radLat1 - radLat2;
   double b = rad(lng1) - rad(lng2);
   double s = 2 * asin(sqrt(pow(sin(a/2),2) +cos(radLat1)*cos(radLat2)*pow(sin(b/2),2)));
   s = s * EARTH_RADIUS;
   s = round(s * 10000) / 10000;
   return s;
}




int main(int argc, char** argv) {
    double d = get_distance(40.0706,116.588717,40.070917,116.588684);
    cout<<d*1000<<"m"<<endl;
}

以上代码已经过测试。