Formatting floating point numbers

Author: ref-humbold

src/main/java/com/github/refhumbold/algolib/geometry/dim2/Angle.java

@@ -1,5 +1,6 @@
 package com.github.refhumbold.algolib.geometry.dim2;
 
+import java.text.DecimalFormat;
 import java.util.Objects;
 import com.github.refhumbold.algolib.geometry.GeometryComparator;
 
@@ -53,4 +54,12 @@ public int compareTo(Angle angle)
     {
         return angle == null ? 1 : comparator.compare(degrees, angle.degrees);
     }
+
+    @Override
+    public String toString()
+    {
+        var df = new DecimalFormat("0.0###########");
+
+        return "Angle(%s deg)".formatted(df.format(degrees));
+    }
 }

src/main/java/com/github/refhumbold/algolib/geometry/dim2/Point2D.java

@@ -1,5 +1,6 @@
 package com.github.refhumbold.algolib.geometry.dim2;
 
+import java.text.DecimalFormat;
 import java.util.Objects;
 import com.github.refhumbold.algolib.geometry.GeometryComparator;
 
@@ -43,7 +44,9 @@ public int hashCode()
     @Override
     public String toString()
     {
-        return "(%f, %f)".formatted(x, y);
+        var df = new DecimalFormat("0.0###########");
+
+        return "(%s, %s)".formatted(df.format(x), df.format(y));
     }
 
     public double radius()

src/main/java/com/github/refhumbold/algolib/geometry/dim2/Vector2D.java

@@ -1,5 +1,6 @@
 package com.github.refhumbold.algolib.geometry.dim2;
 
+import java.text.DecimalFormat;
 import java.util.Objects;
 import com.github.refhumbold.algolib.geometry.GeometryComparator;
 
@@ -58,7 +59,9 @@ public int hashCode()
     @Override
     public String toString()
     {
-        return "[%f, %f]".formatted(x, y);
+        var df = new DecimalFormat("0.0###########");
+
+        return "[%s, %s]".formatted(df.format(x), df.format(y));
     }
 
     public double length()

src/main/java/com/github/refhumbold/algolib/geometry/dim3/Point3D.java

@@ -1,5 +1,6 @@
 package com.github.refhumbold.algolib.geometry.dim3;
 
+import java.text.DecimalFormat;
 import java.util.Objects;
 import com.github.refhumbold.algolib.geometry.GeometryComparator;
 
@@ -45,7 +46,9 @@ public int hashCode()
     @Override
     public String toString()
     {
-        return "(%f, %f, %f)".formatted(x, y, z);
+        var df = new DecimalFormat("0.0###########");
+
+        return "(%s, %s, %s)".formatted(df.format(x), df.format(y), df.format(z));
     }
 
     public double radius()

src/main/java/com/github/refhumbold/algolib/geometry/dim3/Vector3D.java

@@ -1,5 +1,6 @@
 package com.github.refhumbold.algolib.geometry.dim3;
 
+import java.text.DecimalFormat;
 import java.util.Objects;
 import com.github.refhumbold.algolib.geometry.GeometryComparator;
 
@@ -71,7 +72,9 @@ public int hashCode()
     @Override
     public String toString()
     {
-        return "[%f, %f, %f]".formatted(x, y, z);
+        var df = new DecimalFormat("0.0###########");
+
+        return "[%s, %s, %s]".formatted(df.format(x), df.format(y), df.format(z));
     }
 
     public double length()

src/main/java/com/github/refhumbold/algolib/maths/Equation.java

@@ -1,9 +1,7 @@
 package com.github.refhumbold.algolib.maths;
 
 import java.text.DecimalFormat;
-import java.text.DecimalFormatSymbols;
 import java.util.Arrays;
-import java.util.Locale;
 import java.util.stream.Collectors;
 import java.util.stream.IntStream;
 
@@ -37,7 +35,8 @@ public static Equation of(double[] coefficients, double free)
     @Override
     public String toString()
     {
-        DecimalFormat df = new DecimalFormat("", DecimalFormatSymbols.getInstance(Locale.ENGLISH));
+        var df = new DecimalFormat("0.############");
+
         return IntStream.range(0, coefficients.length)
                         .filter(i -> coefficients[i] != 0)
                         .mapToObj(i -> "%s x_%d".formatted(df.format(coefficients[i]), i))

src/test/java/com/github/refhumbold/algolib/geometry/dim2/AngleTest.java

@@ -3,6 +3,7 @@
 import java.util.stream.Stream;
 import org.assertj.core.api.Assertions;
 import org.assertj.core.data.Offset;
+import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -40,6 +41,16 @@ public void radians_WhenFromDegrees_ThenPositiveRadiansInRange(double degrees, d
         Assertions.assertThat(result).isCloseTo(radians, OFFSET);
     }
 
+    @Test
+    public void toString_ThenStringRepresentation()
+    {
+        // when
+        String result = Angle.fromDegrees(150.123456789).toString();
+
+        // then
+        Assertions.assertThat(result).isEqualTo("Angle(150.123456789 deg)");
+    }
+
     private static Stream<Arguments> paramsFor_degrees_WhenFromRadians()
     {
         return Stream.of(Arguments.of(0.0, 0.0), Arguments.of(Math.PI / 6, 30.0),