From 3af4cfd7c8e83df8f7018d802c61f9c22296e729 Mon Sep 17 00:00:00 2001
From: Byte Bender <136265142+BYT-Bender@users.noreply.github.com>
Date: Tue, 15 Oct 2024 01:32:40 +0530
Subject: [PATCH] Add SumOfOddNumbers (#5730)

---
 .../thealgorithms/maths/SumOfOddNumbers.java  | 25 +++++++++++++++++
 .../maths/SumOfOddNumbersTest.java            | 28 +++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java
 create mode 100644 src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java

diff --git a/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java b/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java
new file mode 100644
index 000000000..c0a1e7826
--- /dev/null
+++ b/src/main/java/com/thealgorithms/maths/SumOfOddNumbers.java
@@ -0,0 +1,25 @@
+package com.thealgorithms.maths;
+
+/**
+ * This program calculates the sum of the first n odd numbers.
+ *
+ * https://www.cuemath.com/algebra/sum-of-odd-numbers/
+ */
+
+public final class SumOfOddNumbers {
+    private SumOfOddNumbers() {
+    }
+
+    /**
+     * Calculate sum of the first n odd numbers
+     *
+     * @param n the number of odd numbers to sum
+     * @return sum of the first n odd numbers
+     */
+    public static int sumOfFirstNOddNumbers(final int n) {
+        if (n < 0) {
+            throw new IllegalArgumentException("n must be non-negative.");
+        }
+        return n * n;
+    }
+}
diff --git a/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java b/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java
new file mode 100644
index 000000000..6470d7983
--- /dev/null
+++ b/src/test/java/com/thealgorithms/maths/SumOfOddNumbersTest.java
@@ -0,0 +1,28 @@
+package com.thealgorithms.maths;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.util.stream.Stream;
+import org.junit.jupiter.api.Assertions;
+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;
+
+public class SumOfOddNumbersTest {
+
+    @ParameterizedTest
+    @MethodSource("inputStream")
+    void sumOfFirstNOddNumbersTests(int expected, int input) {
+        Assertions.assertEquals(expected, SumOfOddNumbers.sumOfFirstNOddNumbers(input));
+    }
+
+    private static Stream<Arguments> inputStream() {
+        return Stream.of(Arguments.of(1, 1), Arguments.of(4, 2), Arguments.of(9, 3), Arguments.of(16, 4), Arguments.of(25, 5), Arguments.of(100, 10));
+    }
+
+    @Test
+    public void testSumOfFirstNOddNumbersThrowsExceptionForNegativeInput() {
+        assertThrows(IllegalArgumentException.class, () -> SumOfOddNumbers.sumOfFirstNOddNumbers(-1));
+    }
+}