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ComputerScience109/Main.java

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+/*
+ * in this Java program, the user can calculate the area of a rectangle,
+ *  and the volumes of a cube, cylinder, and sphere.
+ * The user will be prompt to enter the length and width of a rectangle,
+ * and then choose a shape to calculate the volume of (cube, cylinder, or sphere).
+ */
+
+import java.util.InputMismatchException;
+import java.util.Scanner;
+
+class Rectangle {
+    public static double rectangleArea(double length, double width) {
+        return length * width;
+    }
+}
+
+class Cube {
+    public static double cubeVolume(double side) {
+        return Math.pow(side, 3);
+    }
+}
+
+class Cylinder {
+    public static double cylinderVolume(double radius, double height) {
+        return Math.PI * Math.pow(radius, 2) * height;
+    }
+}
+
+class Sphere {
+    public static double sphereVolume(double radius) {
+        return (4.0 / 3.0) * Math.PI * Math.pow(radius, 3);
+    }
+}
+//Main Class
+
+public class Main{
+
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+
+        try {
+            // User prompt for the length and width
+            System.out.println("Rectangle Area");
+            System.out.print("Please enter length: ");
+            double length = scanner.nextDouble();
+
+            System.out.print("Please enter width: ");
+            double width = scanner.nextDouble();
+
+// making sure that the user put positive numbers otherwise we throw a //warning
+
+            if (length <= 0 || width <= 0) {
+                System.out.println("WARNING!: Length and width must be positive numbers.");
+            } else {
+                double area = Rectangle.rectangleArea(length, width);
+                System.out.println("Rectangle Area: " + area);
+            }
+
+            // Choose shape for volume calculation
+
+            System.out.println("");
+            System.out.println("Volume Calculation");
+            System.out.println("Choose a shape to calculate volume:");
+            System.out.println("1. Cube");
+            System.out.println("2. Cylinder ");
+            System.out.println("3. Sphere ");
+            System.out.print("Enter your choice (1-3): ");
+            int userChoice = scanner.nextInt();
+
+
+
+            switch (userChoice) {
+                case 1:
+                    System.out.print("Enter side length of cube: ");
+                    double side = scanner.nextDouble();
+                    if (side <= 0) {
+                        System.out.println("Error: Side must be a positive number.");
+                    } else {
+                        double cubeVolume = Cube.cubeVolume(side);
+                        System.out.println("Cube Volume: " + cubeVolume);
+                    }
+                    break;
+                case 2:
+                    System.out.print("Enter radius of cylinder: ");
+                    double cylinderRadius = scanner.nextDouble();
+                    System.out.print("Enter height of cylinder: ");
+                    double cylinderHeight = scanner.nextDouble();
+                    if (cylinderRadius <= 0 || cylinderHeight <= 0) {
+                        System.out.println("Error: Radius and height must be positive numbers.");
+                    } else {
+                        double cylinderVolume = Cylinder.cylinderVolume(cylinderRadius, cylinderHeight);
+                        System.out.println("Cylinder Volume: " + cylinderVolume);
+                    }
+                    break;
+                case 3:
+                    System.out.print("Enter radius of sphere: ");
+                    double sphereRadius = scanner.nextDouble();
+                    if (sphereRadius <= 0) {
+                        System.out.println("Error: Radius must be a positive number.");
+                    } else {
+                        double sphereVolume = Sphere.sphereVolume(sphereRadius);
+                        System.out.println("Sphere Volume: " + sphereVolume);
+                    }
+                    break;
+                default:
+                    System.out.println("Invalid choice.");
+            }
+
+        } catch (InputMismatchException e) {
+            System.out.println("Input error: Please enter valid numeric values.");
+        } finally {
+            scanner.close();
+        }
+    }
+}
+
+//Please copy and paste this code to an IDE and run
+

ComputerScience109/PerfectNumbers.java

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+import java.util.Scanner;
+/*
+ * The program below is a java script that helps find the perfect numbers using
+ * Nested Loops.
+ * A perfect numbersber is a positive integer that equals the sum of its
+ * proper positive divisors (excluding the number itself)
+ * */
+
+public class PerfectNumbers {
+
+  public static void main(String[] args) {
+    // Part 1: Find perfect numbers between 1 and 200
+    System.out.println("Perfect Numbers between 1 and 200:");
+    // findAndPrintPerfectNumber(200);
+
+    // Add a separator line in the output.
+    System.out.println("\n----------------------------------------\n");
+
+    // Part 2: User input range (up to maximum of 1000)
+    Scanner scanner = new Scanner(System.in);
+
+    int upperBound;
+    do {
+      System.out.print("Enter an upper bound between 1 and 1000 for checking perfect numbers: ");
+      while (!scanner.hasNextInt()) { // Validate integer input.
+        System.out.println("That's not a valid number. Please enter an integer.");
+        scanner.next(); // discard invalid input
+        System.out.print("Enter an upper bound between 1 and 1000: ");
+      }
+      upperBound = scanner.nextInt();
+
+      if (upperBound < 1 || upperBound > 9000) {
+        System.out.println("Please enter a number between 1 and 1000.");
+      } else {
+        break;
+      }
+    } while (true);
+
+    // Now check for perfect numbers in the user-specified range.
+    System.out.println("\nPerfect Numbers between 1 and " + upperBound + ":");
+    // findAndPrintPerfectNumber(upperBound);
+
+    scanner.close();
+  }
+
+  /**
+   * This method finds and prints all perfect numbers up to a given limit
+   * (inclusive).
+   */
+  public static void perfectNums() {
+    // Let's get the perfect numbers in the a range of positive integers ( 1 to 200)
+    // OUTER LOOP
+    for (int i = 1; i <= 200; i++) {
+      int total = 0;
+      // INNER LOOP
+      for (int j = 1; j <= i / 2; j++) {
+        total += j;
+      }
+
+      if (total == i) {
+        System.out.println(i + " is a perfect number");
+      }
+    }
+  }
+  // public static void findAndPrintPerfectNumber(int limit) {
+  // for (int i = 1; i <= limit; i++) { // Loop through each number
+  // int sumOfDivisors = 0;
+  //
+  // // Find proper divisors using nested loops.
+  // // Note: Instead of a nested loop, we can iterate up to half of the number,
+  // // but since you requested a nested loop approach, here's how it might look:
+  // for (int j = 1; j <= i / 2; j++) { // Only need to check up to i/2
+  // if (i % j == 0) {
+  // sumOfDivisors += j;
+  // }
+  // }
+  //
+  // // Check if the number is perfect.
+  // if (sumOfDivisors == i && i != 1) { // Exclude 1 as it's not considered a
+  // perfect number
+  // System.out.println(i);
+  // }
+  // }
+  // }
+}