direction.cpp

给出地球上两点的经纬度

#include <math.h>
#include "stdio.h"
FILE *fp1;
#define PI 3.1415926265



void main()
{  float  W1=41.19544*PI/180,J1=123.02825*PI/180;
   float W2=41.2036666666666666667*PI/180,J2=123.0315555555555555556*PI/180;
   float  W3=41.213555555555555556*PI/180,J3=123.026388888888888889*PI/180;
   double r12,r13,s12,s13,r;
   r=20000/3.141592625;
   r12=pow(cos(W1)*cos(J1)-cos(W2)*cos(J2),2)+pow(cos(W1)*sin(J1)-cos(W2)*sin(J2),2)+pow(cos(W1)-cos(W2),2);
printf("r12=%f\n",r12);  
   r13=pow(cos(W1)*cos(J1)-cos(W3)*cos(J3),2)+pow(cos(W1)*sin(J1)-cos(W3)*sin(J3),2)+pow(cos(W1)-cos(W3),2);
   printf("r=%f\n",r);

   r12=sqrt(r12);

   r13=sqrt(r13);


   ////修正
   s12=acos((2-r12*r12)/2)*r;
   s13=acos((2-r13*r13)/2)*r;
   
   fp1=fopen("ls.txt","w+");
       fprintf(fp1,"START===================================================WRITE\n");
   

   fprintf(fp1,"r12=%f\nr13=%f\ns12=%-10.10f\ns13=%-10.10f",r12,r13,s12,s13);
   fclose(fp1);

}