From 451ed75a90afbfb154e7712f800b81bdbb9d9187 Mon Sep 17 00:00:00 2001
From: navaneedan07 <navaneedannaveen07@gmail.com>
Date: Thu, 31 Jul 2025 19:57:43 +0530
Subject: [PATCH 1/3] Refactored ReverseStringUsingStack

---
 src/test/java/com/thealgorithms/strings/ReverseStringTest.java | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 08f5fb586d82..9f13d82c75b9 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -3,6 +3,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import java.util.stream.Stream;
+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;

From b7fbbcd97811a19b1ded992fcb667d991022d25e Mon Sep 17 00:00:00 2001
From: navaneedan07 <navaneedannaveen07@gmail.com>
Date: Thu, 31 Jul 2025 20:09:42 +0530
Subject: [PATCH 2/3] Add ReverseStringUsingStack

---
 .../stacks/ReverseStringUsingStack.java       | 34 ++++++++++++++
 .../thealgorithms/strings/ReverseString.java  | 29 ++++++++++++
 .../stacks/ReverseStringUsingStackTest.java   | 44 +++++++++++++++++++
 .../strings/ReverseStringTest.java            | 12 +++++
 4 files changed, 119 insertions(+)
 create mode 100644 src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java
 create mode 100644 src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java b/src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java
new file mode 100644
index 000000000000..9e4c1ac9d1be
--- /dev/null
+++ b/src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java
@@ -0,0 +1,34 @@
+package com.thealgorithms.stacks;
+
+import java.util.Stack;
+
+public final class ReverseStringUsingStack {
+    private ReverseStringUsingStack() {
+    }
+
+    /**
+     * @param str string to be reversed using stack
+     * @return reversed string
+     */
+    public static String reverse(String str) {
+        // Check if the input string is null
+        if (str == null) {
+            throw new IllegalArgumentException("Input string cannot be null");
+        }
+        Stack<Character> stack = new Stack<>();
+        StringBuilder reversedString = new StringBuilder();
+        // Check if the input string is empty
+        if (str.isEmpty()) {
+            return str;
+        }
+        // Push each character of the string onto the stack
+        for (char ch : str.toCharArray()) {
+            stack.push(ch);
+        }
+        // Pop each character from the stack and append to the StringBuilder
+        while (!stack.isEmpty()) {
+            reversedString.append(stack.pop());
+        }
+        return reversedString.toString();
+    }
+}
diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index 54a9b779e828..4969ac83e9dd 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -1,5 +1,7 @@
 package com.thealgorithms.strings;
 
+import java.util.Stack;
+
 /**
  * Reverse String using different version
  */
@@ -57,4 +59,31 @@ public static String reverse3(String string) {
         }
         return sb.toString();
     }
+    /**
+     * Reverses the given string using a stack.
+     * This method uses a stack to reverse the characters of the string.
+     * * @param str The input string to be reversed.
+     * @return The reversed string.
+     */
+    public static String reverse4(String str) {
+        // Check if the input string is null
+        if (str == null) {
+            throw new IllegalArgumentException("Input string cannot be null");
+        }
+        Stack<Character> stack = new Stack<>();
+        StringBuilder reversedString = new StringBuilder();
+        // Check if the input string is empty
+        if (str.isEmpty()) {
+            return str;
+        }
+        // Push each character of the string onto the stack
+        for (char ch : str.toCharArray()) {
+            stack.push(ch);
+        }
+        // Pop each character from the stack and append to the StringBuilder
+        while (!stack.isEmpty()) {
+            reversedString.append(stack.pop());
+        }
+        return reversedString.toString();
+    }
 }
diff --git a/src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java b/src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java
new file mode 100644
index 000000000000..cfd3ffee667b
--- /dev/null
+++ b/src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java
@@ -0,0 +1,44 @@
+package com.thealgorithms.stacks;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import org.junit.jupiter.api.Test;
+
+class ReverseStringUsingStackTest {
+
+    @Test
+    void testRegularString() {
+        assertEquals("olleh", ReverseStringUsingStack.reverse("hello"));
+    }
+
+    @Test
+    void testEmptyString() {
+        assertEquals("", ReverseStringUsingStack.reverse(""));
+    }
+
+    @Test
+    void testPalindromeString() {
+        assertEquals("madam", ReverseStringUsingStack.reverse("madam"));
+    }
+
+    @Test
+    void testSpecialCharacters() {
+        assertEquals("#@!321cba", ReverseStringUsingStack.reverse("abc123!@#"));
+    }
+
+    @Test
+    void testSingleCharacter() {
+        assertEquals("x", ReverseStringUsingStack.reverse("x"));
+    }
+
+    @Test
+    void testWhitespaceHandling() {
+        assertEquals("dlroW olleH", ReverseStringUsingStack.reverse("Hello World"));
+    }
+
+    @Test
+    void testNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> { ReverseStringUsingStack.reverse(null); });
+    }
+}
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 9f13d82c75b9..9a7538f216c4 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -1,6 +1,7 @@
 package com.thealgorithms.strings;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
@@ -32,4 +33,15 @@ public void testReverseString2(String input, String expectedOutput) {
     public void testReverseString3(String input, String expectedOutput) {
         assertEquals(expectedOutput, ReverseString.reverse3(input));
     }
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void testReverseString4(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverse4(input));
+    }
+
+    @Test
+    public void testReverseString4WithNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> ReverseString.reverse4(null));
+    }
 }

From ceb6b93ba07b455f42f343786079c9c6442ef19e Mon Sep 17 00:00:00 2001
From: navaneedan07 <navaneedannaveen07@gmail.com>
Date: Fri, 1 Aug 2025 15:21:43 +0530
Subject: [PATCH 3/3] Refactored ReverseStringUsingStack

---
 .../stacks/ReverseStringUsingStack.java       | 34 --------------
 .../thealgorithms/strings/ReverseString.java  |  2 +-
 .../stacks/ReverseStringUsingStackTest.java   | 44 -------------------
 .../strings/ReverseStringTest.java            |  8 ++--
 4 files changed, 5 insertions(+), 83 deletions(-)
 delete mode 100644 src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java
 delete mode 100644 src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java

diff --git a/src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java b/src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java
deleted file mode 100644
index 9e4c1ac9d1be..000000000000
--- a/src/main/java/com/thealgorithms/stacks/ReverseStringUsingStack.java
+++ /dev/null
@@ -1,34 +0,0 @@
-package com.thealgorithms.stacks;
-
-import java.util.Stack;
-
-public final class ReverseStringUsingStack {
-    private ReverseStringUsingStack() {
-    }
-
-    /**
-     * @param str string to be reversed using stack
-     * @return reversed string
-     */
-    public static String reverse(String str) {
-        // Check if the input string is null
-        if (str == null) {
-            throw new IllegalArgumentException("Input string cannot be null");
-        }
-        Stack<Character> stack = new Stack<>();
-        StringBuilder reversedString = new StringBuilder();
-        // Check if the input string is empty
-        if (str.isEmpty()) {
-            return str;
-        }
-        // Push each character of the string onto the stack
-        for (char ch : str.toCharArray()) {
-            stack.push(ch);
-        }
-        // Pop each character from the stack and append to the StringBuilder
-        while (!stack.isEmpty()) {
-            reversedString.append(stack.pop());
-        }
-        return reversedString.toString();
-    }
-}
diff --git a/src/main/java/com/thealgorithms/strings/ReverseString.java b/src/main/java/com/thealgorithms/strings/ReverseString.java
index 4969ac83e9dd..996aa68bb307 100644
--- a/src/main/java/com/thealgorithms/strings/ReverseString.java
+++ b/src/main/java/com/thealgorithms/strings/ReverseString.java
@@ -65,7 +65,7 @@ public static String reverse3(String string) {
      * * @param str The input string to be reversed.
      * @return The reversed string.
      */
-    public static String reverse4(String str) {
+    public static String reverseStringUsingStack(String str) {
         // Check if the input string is null
         if (str == null) {
             throw new IllegalArgumentException("Input string cannot be null");
diff --git a/src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java b/src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java
deleted file mode 100644
index cfd3ffee667b..000000000000
--- a/src/test/java/com/thealgorithms/stacks/ReverseStringUsingStackTest.java
+++ /dev/null
@@ -1,44 +0,0 @@
-package com.thealgorithms.stacks;
-
-import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
-import org.junit.jupiter.api.Test;
-
-class ReverseStringUsingStackTest {
-
-    @Test
-    void testRegularString() {
-        assertEquals("olleh", ReverseStringUsingStack.reverse("hello"));
-    }
-
-    @Test
-    void testEmptyString() {
-        assertEquals("", ReverseStringUsingStack.reverse(""));
-    }
-
-    @Test
-    void testPalindromeString() {
-        assertEquals("madam", ReverseStringUsingStack.reverse("madam"));
-    }
-
-    @Test
-    void testSpecialCharacters() {
-        assertEquals("#@!321cba", ReverseStringUsingStack.reverse("abc123!@#"));
-    }
-
-    @Test
-    void testSingleCharacter() {
-        assertEquals("x", ReverseStringUsingStack.reverse("x"));
-    }
-
-    @Test
-    void testWhitespaceHandling() {
-        assertEquals("dlroW olleH", ReverseStringUsingStack.reverse("Hello World"));
-    }
-
-    @Test
-    void testNullInput() {
-        assertThrows(IllegalArgumentException.class, () -> { ReverseStringUsingStack.reverse(null); });
-    }
-}
diff --git a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
index 9a7538f216c4..476765b00dfc 100644
--- a/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
+++ b/src/test/java/com/thealgorithms/strings/ReverseStringTest.java
@@ -36,12 +36,12 @@ public void testReverseString3(String input, String expectedOutput) {
 
     @ParameterizedTest
     @MethodSource("testCases")
-    public void testReverseString4(String input, String expectedOutput) {
-        assertEquals(expectedOutput, ReverseString.reverse4(input));
+    public void testReverseStringUsingStack(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseString.reverseStringUsingStack(input));
     }
 
     @Test
-    public void testReverseString4WithNullInput() {
-        assertThrows(IllegalArgumentException.class, () -> ReverseString.reverse4(null));
+    public void testReverseStringUsingStackWithNullInput() {
+        assertThrows(IllegalArgumentException.class, () -> ReverseString.reverseStringUsingStack(null));
     }
 }

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