uva_190.cppl(working with line )

#include<bits/stdc++.h>
using namespace std ;

#define M 999999999999999999
#define pii pair<int , int >
#define mp make_pair
#define pf printf
#define sf scanf
#define sf1(a ) scanf("%d",&a)
#define pb push_back
#define sf2(a, b) scanf("%d%d",&a ,&b)
#define rep(i,n ) for(i = 0 ; i< n ;i++ )

typedef long long LL ;
LL num ;

struct  _line{
double a  , b ,c , m  , mid_x, mid_y ;

};

struct _point
{
  double x , y;
};

vector<_line> line ;
vector<_point> point ;
double p_1 , p_2;

void call(_point p1 , _point p2); // makes line eqn from 2 points
void make_line(_line p1   );
int i_sec(_line p1 , _line p2);

void print(double rad){
double c ;
c =  p_1*p_1 +p_2*p_2 - rad*rad ;

  /*if(p_1 == 0 && p_2 == 0){
      pf("x^2 + y^2 = %.3lf^2\n",rad );
    if(c < 0)
    pf("x^2 + y^2 - %.3lf = 0\n",p_1*2 , p_2*2,-c );
    else
        pf("x^2 + y^2 + %.3lf = 0\n",p_1*2 , p_2*2,c );
    return ;
  }
  else if(p_1 ==  0){
     pf("x^2 + (y - %.3lf)^2 = %.3lf^2\n", p_2 ,rad );
    if(c < 0)
    pf("x^2 + y^2 - %.3lfy - %.3lf = 0\n" , p_2*2,-c );
    else
        pf("x^2 + y^2 - %.3lfy + %.3lf = 0\n", p_2*2,c );
 }
  else if(p_2 == 0)
  {
    pf("(x - %.3lf)^2 + y^2 = %.3lf^2\n",p_1 ,rad );
    if(c < 0)
    pf("x^2 + y^2 - %.3lfx - %.3lf = 0\n",p_1*2 ,-c );
    else
        pf("x^2 + y^2 - %.3lfx + %.3lf = 0\n",p_1*2 ,c );


  }*/

   if(p_1 > 0 && p_2 > 0){
    pf("(x - %.3lf)^2 + (y - %.3lf)^2 = %.3lf^2\n",p_1 , p_2 ,rad );
    if(c < 0)
    pf("x^2 + y^2 - %.3lfx - %.3lfy - %.3lf = 0\n",p_1*2 , p_2*2,-c );
    else
        pf("x^2 + y^2 - %.3lfx - %.3lfy + %.3lf = 0\n",p_1*2 , p_2*2,c );

  }
  else if(p_1 < 0  && p_2< 0){
     pf("(x + %.3lf)^2 + (y + %.3lf)^2 = %.3lf^2\n",-p_1 , -p_2 ,rad );
     if(c >= 0)
     pf("x^2 + y^2 + %.3lfx + %.3lfy + %.3lf = 0\n",-p_1*2 , -p_2*2,c );
   else
      pf("x^2 + y^2 + %.3lfx + %.3lfy - %.3lf = 0\n",-p_1*2 , -p_2*2,-c );


  }
  else if(p_1 < 0 && p_2 > 0){

    pf("(x + %.3lf)^2 + (y - %.3lf)^2 = %.3lf^2\n",-p_1 , p_2 ,rad );
     if(c >= 0)
        pf("x^2 + y^2 + %.3lfx - %.3lfy + %.3lf = 0\n",-p_1*2 , p_2*2,c );
     else
        pf("x^2 + y^2 + %.3lfx - %.3lfy - %.3lf = 0\n",-p_1*2 , p_2*2,-c);


  }
  else if(p_1 >0 && p_2 <0){

    pf("(x - %.3lf)^2 + (y + %.3lf)^2 = %.3lf^2\n",p_1 , -p_2 ,rad );
     if(c >= 0)
        pf("x^2 + y^2 - %.3lfx + %.3lfy + %.3lf = 0\n",p_1*2 , -p_2*2,c );
     else
        pf("x^2 + y^2 - %.3lfx + %.3lfy - %.3lf = 0\n",p_1*2 , -p_2*2,-c );



  }

  return ;
}


int main(){
freopen("in.txt","r",stdin );
freopen("out.txt","w",stdout );


double x1 , y1 ;
int i , j ,k ;
while(  scanf("%lf %lf",&x1 , &y1)==2 ){
  point.clear();
  line.clear();
_point pvar;

  pvar.x = x1;
  pvar.y = y1 ;
  point.push_back(pvar);

  for(i = 2;i<= 3 ; i++){
    scanf("%lf %lf",&x1 , &y1);
    pvar.x = x1;
    pvar.y = y1 ;
    point.push_back(pvar);
  }

  call(point[0]  , point[1]);
  call(point[1]  , point[2]);
  call(point[2]  , point[0]);

   /* for(i = 0  ;i< 3 ;i++)
    {
        _line v ;
        v  = line[i];
      //  pf("line %d  : %lf %lf %lf %lf %lf %lf\n",i ,v.a , v.b , v.c , v.m ,v.mid_x , v.mid_y);


    }
*/
  make_line(line[0] );
  make_line(line[1] );
  make_line(line[2] );
//pf("printing derived line\n");
  //  for(i = 3  ;i< 6 ;i++)
    //{
     //   _line v ;
       // v  = line[i];
   //     pf("line %d  : %lf %lf %lf %lf %lf %lf\n",i ,v.a , v.b , v.c , v.m ,v.mid_x , v.mid_y);


   // }
  i_sec(line[3] ,line[4]);
 // pf("intersecting %lf %lf\n",p_1 , p_2 );
double rad ;
  rad  = sqrt((p_1 - point[0].x)*(p_1 - point[0].x) + (p_2 - point[0].y)*(p_2 - point[0].y));
//  pf("intersecting %lf %lf %lf\n",p_1 , p_2, rad );
  print(rad);

  pf("\n");


}

  return 0 ;
}




void call(_point p1, _point p2 ){
double x1 ,y1 ,x2, y2 ;
  x1  = p1.x;
  x2 =  p2.x;

  y1 =  p1.y;
  y2 =  p2.y;
 _line var ;

 var.mid_x =( x1 + x2)/2  ;
 var.mid_y = (y1 + y2)/2 ;

if(y1 ==  y2){
  var.a = 0;
  var.b = 1;
  var.c = -y1;
  var.m = 0;
 line.push_back(var);

  return ;
}

else if(x1 == x2 ){
  var.a = 1;
  var.b = 0;
  var.c = -x1;
  var.m = 0;
 line.push_back(var);
  return ;
}
else {

double ret ;
  ret =(double) (y2 - y1)/(x2 -  x1);
  var.a = ret ;
  var.b = -1;
  var.c = -ret*x1  +y1;
 var.m = ret ;
 line.push_back(var);

return ;

  }
}


void make_line(_line p1){

_line var ;
double slope , x1, y1 ;
  slope = var.m = -1/p1.m;
 if(p1.m == 0) slope = 0;
  x1 = p1.mid_x;
  y1 = p1.mid_y;

  var.a =  -slope ;
  var.b = 1;
  var.c =  -y1 + slope*x1;

line.push_back(var);

return ;
}

int i_sec(_line p1 , _line p2){

double ret , ret1, ret2 , x1 ,y1 ,x2 ,y2;
double px1, px2 , py1 ,py2;


double a1, b1 ,c1 , a2 ,b2 ,c2 ;
  a1 = p1.a ;
  b1 = p1.b ;
  c1 = p1.c ;

  a2 = p2.a ;
  b2 = p2.b ;
  c2 = p2.c ;

double hold ,k1 ,k2;
  hold = a1*b2 - a2*b1 ;
 if(hold == 0 ) cout << "trrrrr\n";
  k1 = (double) (b1*c2 - b2*c1)/hold ;
  k2 = (double)(c1*a2 - c2*a1)/hold ;

  p_1  = k1 ;
  p_2 =  k2 ;


}