Language: C++

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

double n, r, x1, y1, x2, y2, x3, y3, xa, ya, xb, yb, xc, yc, ma, mb, mc, y_hasil, x_hasil;

int main(){
	cin >> n;
	for(int i = 1; i <= n; i++){
		cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
		ma = (x2-x1)/(y1-y2);
		mb = (x3-x2)/(y2-y3);
		mc = (x3-x1)/(y1-y3);
		xa = (x1+x2)/2;
		ya = (y1+y2)/2;
		xb = (x2+x3)/2;
		yb = (y2+y3)/2;
		xc = (x3+x1)/2;
		yc = (y3+y1)/2;
		
	//	cout << ma << " " << xa << " " << mb << " " << xb << " " << yb << " " << ya << "\n";
		if(y1 - y2 == 0){
			x_hasil = (x2 + x1) / 2;
			y_hasil = mb*(x_hasil - xb) + yb;
		}else if(y2 - y3 == 0){
			x_hasil = (x2 + x3) / 2;
			y_hasil = ma*(x_hasil - xa) + ya;
		}else{
			x_hasil = (ma*xa - mb*xb + yb - ya)/(ma - mb);
			y_hasil = ma*(x_hasil - xa) + ya;
		}
		
		r = sqrt((x_hasil - x1)*(x_hasil - x1) + (y_hasil - y1)*(y_hasil - y1));
		
		cout << fixed << setprecision(3) << x_hasil << " " << y_hasil << " " << r << "\n";
	}
	return 0;
}

Compiler output:
a.cc:5:18: error: 'double y1' redeclared as different kind of entity
    5 | double n, r, x1, y1, x2, y2, x3, y3, xa, ya, xb, yb, xc, yc, ma, mb, mc, y_hasil, x_hasil;
      |                  ^~
In file included from /usr/include/features.h:523,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/os_defines.h:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/c++config.h:683,
                 from /usr/include/c++/14/cassert:43,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:33,
                 from a.cc:1:
/usr/include/x86_64-linux-gnu/bits/mathcalls.h:257:1: note: previous declaration 'double y1(double)'
  257 | __MATHCALL (y1,, (_Mdouble_));
      | ^~~~~~~~~~
a.cc: In function 'int main()':
a.cc:10:27: error: no match for 'operator>>' (operand types are 'std::basic_istream<char>::__istream_type' {aka 'std::basic_istream<char>'} and 'double(double) noexcept')
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                 ~~~~~~~~~ ^~ ~~
      |                     |        |
      |                     |        double(double) noexcept
      |                     std::basic_istream<char>::__istream_type {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'double (*)(double) noexcept'
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'short int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(short int)y1' to 'short int&'
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'short unsigned int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(short unsigned int)y1' to 'short unsigned int&'
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(int)y1' to 'int&'
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'unsigned int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(unsigned int)y1' to 'unsigned int&'
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'long int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(long int)y1' to 'long int&'
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'long unsigned int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(long unsigned int)y1' to 'long unsigned int&'
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'long long int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(long long int)y1' to 'long long int&'
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'long long unsigned int' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(long long unsigned int)y1' to 'long long unsigned int&'
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'void*' [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |                              ^~
      |                              |
      |                              double (*)(double) noexcept
a.cc:10:30: error: cannot bind rvalue '(void*)y1' to 'void*&'
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:10:30: error: invalid conversion from 'double (*)(double) noexcept' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive]
   10 |                 cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
      |