From 6757bfe86dd907d929b7409ad45344c53d524034 Mon Sep 17 00:00:00 2001
From: Lukas Reichwein <codeisnotevil@gmail.com>
Date: Tue, 16 Jul 2019 17:04:53 +0200
Subject: [PATCH] added division of ComplexNumbers to the ComplexNumber Object.

---
 .../ugsbo/complexnumcalc/ComplexNumber.java   | 20 +++++++++++++
 .../DivideComplexNumbersTest.java             | 30 +++++++++++++++++++
 2 files changed, 50 insertions(+)
 create mode 100644 src/test/java/com/ugsbo/complexnumcalc/DivideComplexNumbersTest.java

diff --git a/src/main/java/com/ugsbo/complexnumcalc/ComplexNumber.java b/src/main/java/com/ugsbo/complexnumcalc/ComplexNumber.java
index cbb6331..3f50272 100644
--- a/src/main/java/com/ugsbo/complexnumcalc/ComplexNumber.java
+++ b/src/main/java/com/ugsbo/complexnumcalc/ComplexNumber.java
@@ -108,4 +108,24 @@ public class ComplexNumber {
         return product;
     }
 
+    /**
+     * Divides the dividend by the divisor, the dividend is this Instance.
+     * 
+     * @param divisor The ComplexNumber by wich this Instance will get divided
+     * @return The Qoutient of the Instance and the divisor
+     */
+    public ComplexNumber divide(ComplexNumber divisor) {
+        Double qoutientRealPart, qoutientImaginaryPart, tempDivisor;
+
+        tempDivisor = divisor.realPart * divisor.realPart + divisor.imaginaryPart * divisor.imaginaryPart;
+        qoutientRealPart = this.realPart * divisor.realPart + this.imaginaryPart * divisor.imaginaryPart;
+        qoutientImaginaryPart = this.imaginaryPart * divisor.realPart - this.realPart * divisor.imaginaryPart;
+        qoutientImaginaryPart /= tempDivisor;
+        qoutientRealPart /= tempDivisor;
+
+        ComplexNumber qoutient = new ComplexNumber(qoutientRealPart, qoutientImaginaryPart);
+
+        return qoutient;
+    }
+
 }
\ No newline at end of file
diff --git a/src/test/java/com/ugsbo/complexnumcalc/DivideComplexNumbersTest.java b/src/test/java/com/ugsbo/complexnumcalc/DivideComplexNumbersTest.java
new file mode 100644
index 0000000..fd0e2e4
--- /dev/null
+++ b/src/test/java/com/ugsbo/complexnumcalc/DivideComplexNumbersTest.java
@@ -0,0 +1,30 @@
+package com.ugsbo.complexnumcalc;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+public class DivideComplexNumbersTest {
+
+    @Test
+    public void divideTwoComplexNumbersWithoutImaginaryPart() {
+        ComplexNumber dividend = new ComplexNumber(Double.valueOf(30), Double.valueOf(0));
+        ComplexNumber divisor = new ComplexNumber(Double.valueOf(6), Double.valueOf(0));
+        ComplexNumber expected = new ComplexNumber(Double.valueOf(5), Double.valueOf(0));
+
+        ComplexNumber quotient = dividend.divide(divisor);
+
+        assertTrue("The quotient is not as expected", quotient.equals(expected));
+    }
+
+    @Test
+    public void divideTwoComplexNumbersWithImaginaryPart() {
+        ComplexNumber dividend = new ComplexNumber(Double.valueOf(30), Double.valueOf(28));
+        ComplexNumber divisor = new ComplexNumber(Double.valueOf(6), Double.valueOf(2));
+        ComplexNumber expected = new ComplexNumber(Double.valueOf(5.9), Double.valueOf(2.7));
+
+        ComplexNumber quotient = dividend.divide(divisor);
+
+        assertTrue("The quotient is not as expected", quotient.equals(expected));
+    }
+}
\ No newline at end of file