Update CalorieCalculator.java

Calorie Calculator/CalorieCalculator.java

@@ -1,54 +1,115 @@
 import java.util.Scanner;
 
 public class CalorieCalculator {
+
+    // Constants for BMR formula coefficients and activity multipliers
+    private static final double MALE_BMR_CONSTANT = 88.362;
+    private static final double FEMALE_BMR_CONSTANT = 447.593;
+    private static final double MALE_WEIGHT_COEFFICIENT = 13.397;
+    private static final double FEMALE_WEIGHT_COEFFICIENT = 9.247;
+    private static final double MALE_HEIGHT_COEFFICIENT = 4.799;
+    private static final double FEMALE_HEIGHT_COEFFICIENT = 3.098;
+    private static final double MALE_AGE_COEFFICIENT = 5.677;
+    private static final double FEMALE_AGE_COEFFICIENT = 4.330;
+
+    private static final double SEDENTARY_MULTIPLIER = 1.2;
+    private static final double MODERATE_MULTIPLIER = 1.55;
+    private static final double ACTIVE_MULTIPLIER = 1.725;
+
     public static void main(String[] args) {
         Scanner scanner = new Scanner(System.in);
 
         // Prompt the user for information
         System.out.println("Calorie Calculator");
+
         System.out.print("Enter your gender (M/F): ");
-        String gender = scanner.nextLine();
-        System.out.print("Enter your age: ");
-        int age = scanner.nextInt();
-        System.out.print("Enter your weight in kilograms: ");
-        double weight = scanner.nextDouble();
-        System.out.print("Enter your height in centimeters: ");
-        double height = scanner.nextDouble();
+        String gender = scanner.nextLine().trim().toUpperCase();
+
+        if (!gender.equals("M") && !gender.equals("F")) {
+            System.out.println("Invalid gender input. Please enter 'M' or 'F'.");
+            return;
+        }
+
+        System.out.print("Enter your age (in years): ");
+        int age = getValidIntInput(scanner);
+
+        System.out.print("Enter your weight (in kilograms): ");
+        double weight = getValidDoubleInput(scanner);
+
+        System.out.print("Enter your height (in centimeters): ");
+        double height = getValidDoubleInput(scanner);
+
         System.out.print("Enter your activity level (sedentary/moderate/active): ");
-        String activityLevel = scanner.next();
+        String activityLevel = scanner.nextLine().trim().toLowerCase();
+
+        if (!isValidActivityLevel(activityLevel)) {
+            System.out.println("Invalid activity level input. Please choose 'sedentary', 'moderate', or 'active'.");
+            return;
+        }
 
         // Calculate BMR
+        double bmr = calculateBMR(gender, age, weight, height);
+
+        // Calculate daily calorie needs based on activity level
+        double calorieNeeds = calculateCalorieNeeds(bmr, activityLevel);
+
+        // Display the results
+        System.out.printf("Your Basal Metabolic Rate (BMR) is: %.0f calories per day.\n", bmr);
+        System.out.printf("Your estimated daily calorie needs are: %.0f calories per day.\n", calorieNeeds);
+
+        scanner.close();
+    }
+
+    // Method to get a valid integer input from the user
+    private static int getValidIntInput(Scanner scanner) {
+        while (!scanner.hasNextInt()) {
+            System.out.println("Invalid input. Please enter a valid integer.");
+            scanner.next();  // Clear invalid input
+        }
+        return scanner.nextInt();
+    }
+
+    // Method to get a valid double input from the user
+    private static double getValidDoubleInput(Scanner scanner) {
+        while (!scanner.hasNextDouble()) {
+            System.out.println("Invalid input. Please enter a valid number.");
+            scanner.next();  // Clear invalid input
+        }
+        return scanner.nextDouble();
+    }
+
+    // Method to check if the activity level is valid
+    private static boolean isValidActivityLevel(String activityLevel) {
+        return activityLevel.equals("sedentary") || activityLevel.equals("moderate") || activityLevel.equals("active");
+    }
+
+    // Method to calculate BMR
+    private static double calculateBMR(String gender, int age, double weight, double height) {
         double bmr;
-        if (gender.equalsIgnoreCase("M")) {
-            bmr = Math.round(88.362 + (13.397 * weight) + (4.799 * height) - (5.677 * age));
-        } else if (gender.equalsIgnoreCase("F")) {
-            bmr = Math.round(447.593 + (9.247 * weight) + (3.098 * height) - (4.330 * age));
+        if (gender.equals("M")) {
+            bmr = MALE_BMR_CONSTANT + (MALE_WEIGHT_COEFFICIENT * weight) + (MALE_HEIGHT_COEFFICIENT * height) - (MALE_AGE_COEFFICIENT * age);
         } else {
-            System.out.println("Invalid gender input.");
-            return;
+            bmr = FEMALE_BMR_CONSTANT + (FEMALE_WEIGHT_COEFFICIENT * weight) + (FEMALE_HEIGHT_COEFFICIENT * height) - (FEMALE_AGE_COEFFICIENT * age);
         }
+        return bmr;
+    }
 
-        // Calculate daily calorie needs based on activity level
+    // Method to calculate calorie needs based on activity level
+    private static double calculateCalorieNeeds(double bmr, String activityLevel) {
         double calorieNeeds;
-        switch (activityLevel.toLowerCase()) {
+        switch (activityLevel) {
             case "sedentary":
-                calorieNeeds = Math.round(bmr * 1.2);
+                calorieNeeds = bmr * SEDENTARY_MULTIPLIER;
                 break;
             case "moderate":
-                calorieNeeds = Math.round(bmr * 1.55);
+                calorieNeeds = bmr * MODERATE_MULTIPLIER;
                 break;
             case "active":
-                calorieNeeds = Math.round(bmr * 1.725);
+                calorieNeeds = bmr * ACTIVE_MULTIPLIER;
                 break;
             default:
-                System.out.println("Invalid activity level input.");
-                return;
+                throw new IllegalArgumentException("Invalid activity level");
         }
-
-        // Display the results
-        System.out.println("Your Basal Metabolic Rate (BMR) is: " + (int) bmr + " calories per day.");
-        System.out.println("Your estimated daily calorie needs are: " + (int) calorieNeeds + " calories per day.");
-
-        scanner.close();
+        return calorieNeeds;
     }
 }