feat: add reverseUsingStringBuilder method to reverse a string

Author: “gozhort”

src/main/java/com/thealgorithms/strings/ReverseStringRecursive.java

@@ -18,4 +18,25 @@ public static String reverse(String str) {
             return reverse(str.substring(1)) + str.charAt(0);
         }
     }
+
+    /**
+     * Reverses the given string using a StringBuilder.
+     * This method converts the string to a character array,
+     * iterates through it in reverse order, and appends each character
+     * to a StringBuilder.
+     *
+     * @param string The input string to be reversed.
+     * @return The reversed string.
+     */
+    public static String reverseUsingStringBuilder(String string){
+        if (string.isEmpty()){
+            return string;
+        }
+        char[] chars = string.toCharArray();
+        StringBuilder sb = new StringBuilder();
+        for (int i = string.length() -1; i >= 0; i--){
+            sb.append(chars[i]);
+        }
+        return sb.toString();
+    }
 }

src/test/java/com/thealgorithms/strings/ReverseStringRecursiveTest.java

@@ -13,4 +13,11 @@ public class ReverseStringRecursiveTest {
     testReverseString(String input, String expectedOutput) {
         assertEquals(expectedOutput, ReverseStringRecursive.reverse(input));
     }
+
+    @ParameterizedTest
+    @CsvSource({"'Hello World', 'dlroW olleH'", "'helloworld', 'dlrowolleh'", "'123456789', '987654321'", "'', ''", "'A', 'A'", "'!123 ABC xyz!', '!zyx CBA 321!'", "'Abc 123 Xyz', 'zyX 321 cbA'", "'12.34,56;78:90', '09:87;65,43.21'", "'abcdEFGHiJKL', 'LKJiHGFEdcba'",
+            "'MixOf123AndText!', '!txeTdnA321fOxiM'"})
+    public void testReverseWithLoop(String input, String expectedOutput) {
+        assertEquals(expectedOutput, ReverseStringRecursive.reverseUsingStringBuilder(input));
+    }
 }