2 files changed, 104 insertions, 0 deletions
diff --git a/src/section-9/Number.java b/src/section-9/Number.java
new file mode 100644
index 0000000..d96274f
--- /dev/null
+++ b/src/section-9/Number.java
@@ -0,0 +1,46 @@
+package ca.mokhan.assignment1;
+
+import java.util.ArrayList;
+
+public class Number {
+  public static boolean isDivisibleBy5(int n) {
+    return isDivisibleBy(n, 5);
+  }
+
+  public static boolean isDivisibleBy7(int n) {
+    return isDivisibleBy(n, 7);
+  }
+
+  public static boolean isOdd(int n) {
+    return !isDivisibleBy(n, 2);
+  }
+
+  public static boolean isPrime(int n) {
+    if (n <= 1) return false;
+
+    for (int i = n - 1; i > 1; i--) if (isDivisibleBy(n, i)) return false;
+
+    return true;
+  }
+
+  public static boolean isDivisibleBy(int n, int denominator) {
+    return n % denominator == 0;
+  }
+
+  public static ArrayList<String> iterate() {
+    ArrayList<String> items = new ArrayList<String>();
+    ArrayList<String> row = new ArrayList<String>();
+    for (Integer i = 0; i < 113; i++) {
+      row.clear();
+      row.add(String.format("%d", i));
+
+      if (isOdd(i)) row.add(String.format("%d is odd", i));
+      if (isDivisibleBy5(i)) row.add("hi five");
+      if (isDivisibleBy7(i + (i + 1))) row.add("wow");
+      if (isPrime(i)) row.add("prime");
+
+      items.add(String.join(",", row));
+    }
+    return items;
+  }
+}
diff --git a/src/section-9/NumberTest.java b/src/section-9/NumberTest.java
new file mode 100644
index 0000000..1ef9d96
--- /dev/null
+++ b/src/section-9/NumberTest.java
@@ -0,0 +1,58 @@
+package ca.mokhan.assignment1;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import junit.framework.Test;
+import junit.framework.TestCase;
+import junit.framework.TestSuite;
+
+public class NumberTest extends TestCase {
+  public NumberTest(String testName) {
+    super(testName);
+  }
+
+  public static Test suite() {
+    return new TestSuite(NumberTest.class);
+  }
+
+  public void testIsDivisibleBy5() {
+    for (int i = 0; i < 113; i++)
+      if (i % 5 == 0) assertTrue(Number.isDivisibleBy5(i));
+      else assertFalse(Number.isDivisibleBy5(i));
+  }
+
+  public void testIsDivisibleBy7() {
+    for (int i = 0; i < 113; i++)
+      if (i % 7 == 0) assertTrue(Number.isDivisibleBy7(i));
+      else assertFalse(Number.isDivisibleBy7(i));
+  }
+
+  public void testIsOdd() {
+    for (int i = 0; i < 113; i++)
+      if (i % 2 == 0) assertFalse(Number.isOdd(i));
+      else assertTrue(Number.isOdd(i));
+  }
+
+  public void testIsPrime() {
+    List<Integer> primes =
+        Arrays.asList(
+            new Integer[] {
+              2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79,
+              83, 89, 97, 101, 103, 107, 109, 113
+            });
+
+    for (Integer i = 0; i < 113; i++)
+      if (primes.contains(i)) assertTrue(Number.isPrime(i));
+      else assertFalse(Number.isPrime(i));
+  }
+
+  public void testIterate() {
+    ArrayList<String> results = Number.iterate();
+    assertTrue(results.contains("0,hi five"));
+    assertTrue(results.contains("1,1 is odd"));
+    assertTrue(results.contains("2,prime"));
+    assertTrue(results.contains("3,3 is odd,wow,prime"));
+    assertTrue(results.contains("4"));
+  }
+}