javajigi · Oct 15, 2018 · Oct 8, 2018 · Oct 15, 2018
diff --git a/src/main/java/coordinate/domain/Point.java b/src/main/java/coordinate/domain/Point.java
@@ -19,18 +19,12 @@ public double calculateLIne(Point point) {
         return Math.sqrt((Math.pow(a,2) + Math.pow(b,2)));
     }
 
-    public Boolean commpareXPoint(Point point) {
-        if (this.xPoint == point.xPoint)  {
-            return true;
-        }
-        return false;
+    public Boolean compareXPoint(Point point) {
+        return this.xPoint == point.xPoint;
     }
 
-    public Boolean commpareYPoint(Point point) {
-        if (this.yPoint == point.yPoint)  {
-            return true;
-        }
-        return false;
+    public Boolean compareYPoint(Point point) {
+        return this.yPoint == point.yPoint;
     }
 
     public int subtractionXPoint(Point point) {

diff --git a/src/main/java/coordinate/domain/Rectangle.java b/src/main/java/coordinate/domain/Rectangle.java
@@ -30,10 +30,10 @@ public String calculate() {
     private int[] findBaseHeight() {
         int[] BaseAndHeight = new int[2];
         for (int i = 1; i < points.size(); i++) {
-            if (points.get(0).commpareXPoint(points.get(i)).equals(true)) {
+            if (points.get(0).compareXPoint(points.get(i)).equals(true)) {
                 BaseAndHeight[0] = points.get(0).subtractionYPoint(points.get(i));
             }
-            if (points.get(0).commpareYPoint(points.get(i)).equals(true)) {
+            if (points.get(0).compareYPoint(points.get(i)).equals(true)) {
                 BaseAndHeight[1] = points.get(0).subtractionXPoint(points.get(i));
             }
         }

diff --git a/src/main/java/coordinate/domain/Triangle.java b/src/main/java/coordinate/domain/Triangle.java
@@ -0,0 +1,36 @@
+package coordinate.domain;
+
+import java.util.ArrayList;
+
+public class Triangle {
+    private ArrayList<Point> points;
+
+    public Triangle(ArrayList<Point> points) {
+        this.points = points;
+    }
+
+    public String calculate() {
+        if (this.points.size() < 3) {
+            return "사각형이 아닙니다.";
+        }
+        if (isTriangle().equals(false)) {
+            throw new IllegalArgumentException("사각형이 아닙니다.");
+        }
+        double[] a = findLine();
+        double s = (a[0] + a[1] + a[2]) / 2;
+        double result = Math.sqrt(s * (s - a[0]) * (s - a[1]) * (s - a[2]));
+        return "삼각형의 면적은 " + result + " 입니다.";
+    }
+
+    private Boolean isTriangle() {
+        return true;
+    }
+
+    private double[] findLine() {
+        double[] lines = new double[3];
+        for (int i = 0; i < 3; i++) {
+            lines[i] = points.get(i).calculateLIne(points.get((i+ 1) % 3));
+        }
+        return lines;
+    }
+}
diff --git a/src/main/java/coordinate/resultview/ResultView.java b/src/main/java/coordinate/resultview/ResultView.java
@@ -1,16 +1,14 @@
 package coordinate.resultview;
 
-import coordinate.domain.CoordinateYLine;
-import coordinate.domain.Line;
-import coordinate.domain.Point;
-import coordinate.domain.Rectangle;
+import coordinate.domain.*;
 import coordinate.utils.CoordinateString;
 
 import java.util.ArrayList;
 import java.util.HashMap;
 
 public class ResultView {
     private static final int FOUR = 4;
+    private static final int T = 3;
     private static final int TWO = 2;
 
     private static final int MAXiMUM_NUM = 24;
@@ -50,6 +48,7 @@ public void toDo(ArrayList<Point> points) {
         HashMap<Integer, String> toDo = new HashMap<>();
         toDo.put(TWO, new Line(points).calculate());
         toDo.put(FOUR, new Rectangle(points).calculate());
+        toDo.put(T, new Triangle(points).calculate());
         displayTest();
         System.out.println(toDo.get(points.size()));
     }

diff --git a/src/test/java/coordinate/CoordinateTest.java b/src/test/java/coordinate/CoordinateTest.java
@@ -26,6 +26,17 @@ public void squareFalseTest() {
         ArrayList<Point> points = PointFactory.testInput(input);
         assertThat(new Rectangle(points).calculate()).isEqualTo("사각형이 아닙니다.");
     }*/
+    @Test
+    public void TriangleTest() {
+        ArrayList<Point> points;
+        String input = "(12,12) - (12, 22) - (22,22)";
+        points = PointFactory.testInput(input);
+        assertThat(new Triangle(points).calculate()).isEqualTo("삼각형의 면적은 50.0 입니다.");
+
+        input = "(10,10)-(14,15)-(20,8)";
+        points = PointFactory.testInput(input);
+        assertThat(new Triangle(points).calculate()).isEqualTo("삼각형의 면적은 28.999999999999996 입니다.");
+    }
 
     @Test
     public void squareTrueTest() {