Dividing summing exercise

P/Sd1/summing/.gitignore → P/Sd1/summing/V1/.gitignore

 /.settings
+/.idea
+/summing.iml
 /.classpath
 /.project
 /target

P/Sd1/summing/V1/pom.xml

+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>de.hdm-stuttgart.sd1</groupId>
+  <artifactId>summing</artifactId>
+  <version>0.9</version>
+
+  <name>Summing</name>
+  <url>https://freedocs.mi.hdm-stuttgart.de</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.12</version>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-core</artifactId>
+      <version>2.9.1</version>
+    </dependency>
+
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+	<groupId>org.apache.maven.plugins</groupId>
+	<artifactId>maven-compiler-plugin</artifactId>
+	<version>3.7.0</version>
+	<configuration>
+	  <source>1.8</source>
+	  <target>1.8</target>
+	</configuration>
+      </plugin>
+
+    </plugins>
+  </build>
+
+</project>

P/Sd1/summing/V1/src/main/java/de/hdm_stuttgart/de/sd1/sum/Summing.java

+package de.hdm_stuttgart.de.sd1.sum;
+
+/**
+ * Summing up integer values.
+ *
+ */
+public class Summing {
+
+  /**
+   * @param args unused
+   */
+  public static void main(String[] args) {
+    // Simple tests
+    System.out.println("1 + 2 + 3" + "=" + getSum(3));
+    System.out.println("1 + 2 + ... + 150" + "=" + getSum(150));
+
+
+    long start = System.nanoTime();
+    System.out.println("1 + 2 + ... + 65535" + "=" + getSum(65535));
+    long end = System.nanoTime();
+    System.out.println("Elapsed time: " + (end - start) + " nanoseconds");
+  }
+  
+  /**
+   * Summing up all integers starting from 0 up to and including a given limit
+   * Example: Let the limit be 5, then the result is 1 + 2 + 3 + 4 + 5  
+   * 
+   * @param limit The last number to include into the computed sum
+   * @return The sum of 1 + 2 + ... + limit
+   */
+  public static long getSum (int limit) {
+    int sum = 0;
+    for (int i = 1; i <= limit; i++) {
+      sum += i;
+    }
+    return sum;
+  }
+}
\ No newline at end of file

P/Sd1/summing/src/test/java/de/hdm_stuttgart/de/sd1/rounding/SummingTest.java → P/Sd1/summing/V1/src/test/java/de/hdm_stuttgart/de/sd1/rounding/SummingTest.java

@@ -11,31 +11,23 @@ import de.hdm_stuttgart.de.sd1.sum.Summing;
  */
 public class SummingTest {
 
-
    /**
-    * Test loop implementation.
+    * Testing negative values and zero.
     */
    @Test
-   public void testSum() {
+   public void testNonPositiveLimits() {
       assertEquals(0, Summing.getSum(-5));
       assertEquals(0, Summing.getSum(0));
-      assertEquals(1, Summing.getSum(1));
-      assertEquals(3, Summing.getSum(2));
-      assertEquals(15, Summing.getSum(5));
-      assertEquals(5050, Summing.getSum(100));
-      assertEquals(2147450880, Summing.getSum(65535));
    }
    /**
-    * Test non-loop implementation.
+    * Testing positive values.
     */
    @Test
-   public void testSumGauss() {
-      assertEquals(0, Summing.getSumUsingGauss(0));
-      assertEquals(1, Summing.getSumUsingGauss(1));
-      assertEquals(3, Summing.getSumUsingGauss(2));
-      assertEquals(2147450880, Summing.getSumUsingGauss(65535));
-      assertEquals(0, Summing.getSumUsingGauss(-5));
-      assertEquals(15, Summing.getSumUsingGauss(5));
-      assertEquals(5050, Summing.getSumUsingGauss(100));
+   public void testPositiveLimits() {
+      assertEquals(1, Summing.getSum(1));
+      assertEquals(3, Summing.getSum(2));
+      assertEquals(15, Summing.getSum(5));
+      assertEquals(5050, Summing.getSum(100)); // Gauss at school
+      assertEquals(2147450880, Summing.getSum(65535));
    }
 }
\ No newline at end of file

P/Sd1/summing/V2/.gitignore

+/.settings
+/.idea
+/summing.iml
+/.classpath
+/.project
+/target

P/Sd1/summing/src/main/java/de/hdm_stuttgart/de/sd1/sum/Summing.java → P/Sd1/summing/V2/src/main/java/de/hdm_stuttgart/de/sd1/sum/Summing.java

@@ -10,7 +10,15 @@ public class Summing {
    * @param args unused
    */
   public static void main(String[] args) {
+    // Simple tests
+    System.out.println("1 + 2 + 3" + "=" + getSum(3));
     System.out.println("1 + 2 + ... + 150" + "=" + getSum(150));
+
+
+    long start = System.nanoTime();
+    System.out.println("1 + 2 + ... + 65535" + "=" + getSum(65535));
+    long end = System.nanoTime();
+    System.out.println("Elapsed time: " + (end - start) + " nanoseconds");
   }
   
   /**
@@ -20,26 +28,12 @@ public class Summing {
    * @param limit The last number to include into the computed sum
    * @return The sum of 1 + 2 + ... + limit
    */
-  public static long getSum (int limit) {
-    int sum = 0;
-    for (int i = 1; i <= limit; i++) {
-      sum += i;
-    }
-    return sum;
-  }
-
-
-  /**
-   * Alternate implementaion offering better performance, see {@link #getSum(int)}
-   * @param limit See {@link #getSum(int)}
-   * @return See {@link #getSum(int)}
-   */
-  public static long getSumUsingGauss (int limit) {
+  public static long getSum(int limit) {
     if (limit < 0) {
       return 0;
-    } else if (0 == limit % 2){
+    } else if (0 == limit % 2){       // even limit, divide by 2
       return limit / 2 * (limit + 1); // Avoiding arithmetic overflow
-    } else {
+    } else {                          // uneven limit, divide (limit + 1 ) by 2
       return (limit + 1) / 2 * limit; // Avoiding arithmetic overflow
     }
   }

P/Sd1/summing/V2/src/test/java/de/hdm_stuttgart/de/sd1/rounding/SummingTest.java

+package de.hdm_stuttgart.de.sd1.rounding;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+import de.hdm_stuttgart.de.sd1.sum.Summing;
+
+/**
+ * Unit tests
+ */
+public class SummingTest {
+
+   /**
+    * Testing negative values and zero.
+    */
+   @Test
+   public void testNonPositiveLimits() {
+      assertEquals(0, Summing.getSum(-5));
+      assertEquals(0, Summing.getSum(0));
+   }
+   /**
+    * Testing positive values.
+    */
+   @Test
+   public void testPositiveLimits() {
+      assertEquals(1, Summing.getSum(1));
+      assertEquals(3, Summing.getSum(2));
+      assertEquals(15, Summing.getSum(5));
+      assertEquals(5050, Summing.getSum(100)); // Gauss at school
+      assertEquals(2147450880, Summing.getSum(65535));
+   }
+}
\ No newline at end of file

P/pom.xml

@@ -47,7 +47,8 @@
     <module>Sd1/Prime/V2</module>
     <module>Sd1/NonsenseGenerator</module>
     <module>Sd1/CollectionImplement/StringSet/Solution</module>
-    <module>Sd1/summing</module>
+    <module>Sd1/summing/V1</module>
+    <module>Sd1/summing/V2</module>
     <module>Sd1/StringLengthSort/Solution</module>
     <module>Sd1/Gcd/V1</module>
     <module>Sd1/interest/V1</module>