Centre and radius of a circle passing through 3 points in a plane: Difference between revisions
Centre and radius of a circle passing through 3 points in a plane (view source)
Revision as of 16:26, 9 June 2024
, 26 days agoAda version
(Added XPL0 example.) |
(Ada version) |
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=={{header|Ada}}==
{{trans|C++}}
<syntaxhighlight lang="ada">procedure Program
is
type Real is digits 2;
package Real_IO is
new Ada.Text_IO.Float_IO (Real);
package Math is
new Ada.Numerics.Generic_Elementary_Functions (Real);
type Point is record
X, Y : Real'Base;
end record;
procedure Find_Circle (P1, P2, P3 : in Point;
Center : out Point;
Radius : out Real)
is
use Math;
X_12 : constant Real'Base := P1.X - P2.X;
X_13 : constant Real'Base := P1.X - P3.X;
Y_12 : constant Real'Base := P1.Y - P2.Y;
Y_13 : constant Real'Base := P1.Y - P3.Y;
Y_31 : constant Real'Base := P3.Y - P1.Y;
Y_21 : constant Real'Base := P2.Y - P1.Y;
X_31 : constant Real'Base := P3.X - P1.X;
X_21 : constant Real'Base := P2.X - P1.X;
SX_13 : constant Real'Base := P1.X**2 - P3.X**2;
SY_13 : constant Real'Base := P1.Y**2 - P3.Y**2;
SX_21 : constant Real'Base := P2.X**2 - P1.X**2;
SY_21 : constant Real'Base := P2.Y**2 - P1.Y**2;
F : constant Real'Base
:= (SX_13 * X_12 + SY_13 * X_12 + SX_21 * X_13 + SY_21 * X_13)
/ (2.0 * (Y_31 * X_12 - Y_21 * X_13));
G : constant Real'Base
:= (SX_13 * Y_12 + SY_13 * Y_12 + SX_21 * Y_13 + SY_21 * Y_13)
/ (2.0 * (X_31 * Y_12 - X_21 * Y_13));
C : constant Real'Base
:= -(P1.X**2) - P1.Y**2 - 2.0 * G * P1.X - 2.0 * F * P1.Y;
H : constant Real'Base := -G;
K : constant Real'Base := -F;
R : constant Real'Base := Sqrt (H * H + K * K - C);
begin
Center.X := H;
Center.Y := K;
Radius := R;
end Find_Circle;
use Ada.Text_IO;
Center : Point;
Radius : Real'Base;
begin
Real_IO.Default_Aft := 2;
Real_IO.Default_Exp := 0;
Find_Circle ((22.83, 2.07), (14.39, 30.24), (33.65, 17.31),
Center, Radius);
Put ("Center is at ("); Real_IO.Put (Center.X);
Put (", "); Real_IO.Put (Center.Y);
Put (")");
New_Line;
Put ("Radius is "); Real_IO.Put (Radius);
New_Line;
end Program;
</syntaxhighlight>
{{out}}
<pre>Center is at (18.98, 16.27)
Radius is 14.71</pre>
=={{header|ALGOL 68}}==
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