Lab 9

src/Aliasing.java

@@ -0,0 +1,25 @@
+import java.awt.Point;
+import java.awt.Rectangle;
+
+public class Aliasing {
+    public static void printPoint(Point p) {
+        System.out.println("(" + p.x + ", " + p.y + ")");
+    }
+
+    public static Point findCenter(Rectangle box) {
+        int x = box.x + box.width / 2;
+        int y = box.y + box.height / 2;
+        return new Point(x, y);
+    }
+
+    public static void main(String[] args) {
+        Rectangle box1 = new Rectangle(2, 4, 7, 9);
+        Point p1 = findCenter(box1); // Creates a new Point object based on box1's coordinates
+        printPoint(p1); // Prints the center of box1
+
+        box1.grow(1, 1); // Increases the size of box1 by 1 unit in all directions
+
+        Point p2 = findCenter(box1); // Creates a new Point object based on the modified box1's coordinates
+        printPoint(p2); // Prints the center of the modified box1
+    }
+}

src/Person.java

@@ -0,0 +1,24 @@
+class Person {
+    private String name;
+
+    public Person(String theName) {
+        this.name = theName;
+    }
+}
+
+public class Student extends Person {
+    private int id;
+    public static int nextId = 1;
+
+    public Student(String theName) {
+        super(theName);
+        id = nextId++;
+    }
+
+    public static void main(String[] args) {
+        Person e1 = new Student("Alice");
+        Person e2 = new Student("Bob");
+        Person e3 = new Student("Carol");
+        Person arrayOfPeople[] = {e1, e2, e3};
+    }
+}

src/StringPlayground.java

@@ -1,4 +1,31 @@
 public class StringPlayground {
+    public static int countParentheses(String s) {
+        int count = 0;
+        for (int i = 0; i < s.length(); i++) {
+            char c = s.charAt(i);
+            if (c == '(') {
+                count++;
+            } else if (c == ')') {
+                count--;
+            }
+        }
+        return count;
+    }
+
     public static void main(String[] args) {
+        String[] testStrings = {
+                "((3 + 7) * 2)", // Balanced
+                "((3 + 7) * 2))", // Unbalanced
+                "((3 + 7) * 2))(", // Unbalanced
+                "", // Empty
+                "((((((", // Unbalanced
+                "))))))", // Unbalanced
+                "()" // Balanced
+        };
+
+        for (String s : testStrings) {
+            int result = countParentheses(s);
+            System.out.println("String: \"" + s + "\", Parentheses Count: " + result);
+        }
     }
-}
+}