Language: C++

#define EPS 1e-10
using namespace std;    

typedef complex<double> P;

double cross(P a, P b){
  return (a.real()*b.imag() - a.imag()*b.real());
}

int main()
{
  int i,j;
  int n;
  P point[3],ans;

  cin >> n;
  for(i=0;i<n;i++){

    for(j=0;j<3;j++){
      cin >> point[j].real() >> point[j].imag();
    }

    P p01 = point[0] + point[1];
    P p12 = point[1] + point[2];
    P h01 = P(p01.real()/2 , p01.imag()/2);
    P h12 = P(p12.real()/2 , p12.imag()/2);
    P n1 = (point[0] - h01) * P(0,1) + h01;
    P n2 = (point[1] - h12) * P(0,1) + h12;

    ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);


    printf("%.3lf %.3lf %.3lf\n",real(ans) + EPS,imag(ans) + EPS,abs(point[0]-ans) );
  }
  return 0;
}

Compiler output:
a.cc:4:9: error: 'complex' does not name a type
    4 | typedef complex<double> P;
      |         ^~~~~~~
a.cc:6:14: error: 'P' was not declared in this scope
    6 | double cross(P a, P b){
      |              ^
a.cc:6:19: error: 'P' was not declared in this scope
    6 | double cross(P a, P b){
      |                   ^
a.cc:6:22: error: expression list treated as compound expression in initializer [-fpermissive]
    6 | double cross(P a, P b){
      |                      ^
a.cc: In function 'int main()':
a.cc:14:3: error: 'P' was not declared in this scope
   14 |   P point[3],ans;
      |   ^
a.cc:16:3: error: 'cin' was not declared in this scope
   16 |   cin >> n;
      |   ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | #define EPS 1e-10
a.cc:20:14: error: 'point' was not declared in this scope; did you mean 'int'?
   20 |       cin >> point[j].real() >> point[j].imag();
      |              ^~~~~
      |              int
a.cc:23:6: error: expected ';' before 'p01'
   23 |     P p01 = point[0] + point[1];
      |      ^~~~
      |      ;
a.cc:24:6: error: expected ';' before 'p12'
   24 |     P p12 = point[1] + point[2];
      |      ^~~~
      |      ;
a.cc:25:6: error: expected ';' before 'h01'
   25 |     P h01 = P(p01.real()/2 , p01.imag()/2);
      |      ^~~~
      |      ;
a.cc:26:6: error: expected ';' before 'h12'
   26 |     P h12 = P(p12.real()/2 , p12.imag()/2);
      |      ^~~~
      |      ;
a.cc:27:6: error: expected ';' before 'n1'
   27 |     P n1 = (point[0] - h01) * P(0,1) + h01;
      |      ^~~
      |      ;
a.cc:28:6: error: expected ';' before 'n2'
   28 |     P n2 = (point[1] - h12) * P(0,1) + h12;
      |      ^~~
      |      ;
a.cc:30:5: error: 'ans' was not declared in this scope
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |     ^~~
a.cc:30:11: error: 'n1' was not declared in this scope; did you mean 'n'?
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |           ^~
      |           n
a.cc:30:17: error: 'h01' was not declared in this scope
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |                 ^~~
a.cc:30:33: error: 'h12' was not declared in this scope
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |                                 ^~~
a.cc:30:37: error: 'n2' was not declared in this scope; did you mean 'n'?
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |                                     ^~
      |                                     n
a.cc:30:45: error: 'cross' cannot be used as a function
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |                                             ^
a.cc:30:68: error: 'cross' cannot be used as a function
   30 |     ans = n1 + (h01-n1) * cross(h12-n2,n2-n1) / cross(h12-n2,h01-n1);
      |                                                                    ^
a.cc:33:34: error: 'real' was not declared in this scope
   33 |     printf("%.3lf %.3lf %.3lf\n",real(ans) + EPS,imag(ans) + EPS,abs(point[0]-ans) );
      |                                  ^~~~
a.cc:33:50: error: 'imag' was not declared in this scope
   33 |     printf("%.3lf %.3lf %.3lf\n",real(ans) + EPS,imag(ans) + EPS,abs(point[0]-ans) );
      |                                                  ^~~~
a.cc:33:70: error: 'point' was not declared in this scope; did you mean 'int'?
   33 |     printf("%.3lf %.3lf %.3lf\n",real(ans) + EPS,imag(ans) + EPS,abs(point[0]-ans) );
      |                                                                      ^~~~~
      |                                                                      int
a.cc:33:66: error: 'abs' was not declared in this scope
   33 |     printf("%.3lf %.3lf %.3lf\n",real(ans) + EPS,imag(ans) + EPS,abs(point[0]-ans) );
      |                                                                  ^~~
a.cc:33:5: error: 'printf' was not declared in this scope
   33 |     printf("%.3lf %.3lf %.3lf\n",real(ans) + EPS,imag(ans) + EPS,abs(point[0]-ans) );
      |     ^~~~~~
a.cc:1:1: note: 'printf' is defined in header '<cstdio>'; this is probably fixable by adding '#include <cstdio>'
  +++ |+#include <cstdio>
    1 | #define EPS 1e-10