www.pudn.com > zhejiang_university_acm_onlinejudge_code.rar > zp1090.cpp

//--------------------------------------------------------------------------- 
 
#pragma hdrstop 
 
//--------------------------------------------------------------------------- 
 
#pragma argsused 
#include  
#include  
#include  
int main(int argc, char* argv[]) 
{ 
  const double pi=3.141592653589793; 
  double c,d,k1,k2,x1,y1,x2,y2,x3,y3,x,y; 
  cout<>x1>>y1>>x2>>y2>>x3>>y3) 
  { 
    if (y1-y3==0) 
    { k1=y3;y3=y2;y2=k1; 
      k1=x3;x3=x2;x2=k1; } 
 
    if (y2-y3==0) 
    { k1=y3;y3=y1;y1=k1; 
      k1=x3;x3=x1;x1=k1; } 
 
    k1=-(x3-x2)/(y3-y2); 
    k2=-(x3-x1)/(y3-y1); 
 
    x=(-y2+y1+k1*(x2+x3)-k2*(x1+x3))/(2*(k1-k2)); 
    y=k1*(x-(x2+x3)/2)+(y2+y3)/2; 
 
    d=sqrt((x1-x)*(x1-x)+(y1-y)*(y1-y)); 
    c=d*pi*2; 
    cout<