Explain and demonstrate Java's increment and decrement operators (++, --) with examples.

public class IncrementDecrement {
    public static void main(String[] args) {
        int x = 10;
        int y = 5;

        System.out.println("Initial value of x: " + x); // x is 10
        System.out.println("Initial value of y: " + y); // y is 5

        // Increment operators
        // Post-increment (x++) - uses current value, then increments
        int a = x++;
        System.out.println("After a = x++: a = " + a + ", x = " + x); // a is 10, x is 11

        // Pre-increment (++y) - increments value, then uses new value
        int b = ++y;
        System.out.println("After b = ++y: b = " + b + ", y = " + y); // b is 6, y is 6

        System.out.println("\n--- Decrement Operators ---");
        int p = 20;
        int q = 15;

        System.out.println("Initial value of p: " + p); // p is 20
        System.out.println("Initial value of q: " + q); // q is 15

        // Decrement operators
        // Post-decrement (p--) - uses current value, then decrements
        int c = p--;
        System.out.println("After c = p--: c = " + c + ", p = " + p); // c is 20, p is 19

        // Pre-decrement (--q) - decrements value, then uses new value
        int d = --q;
        System.out.println("After d = --q: d = " + d + ", q = " + q); // d is 14, q is 14
    }
}

import java.util.Scanner;

public class GradeCalculatorSwitch {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter student's score (0-100): ");
        int score = input.nextInt();
        String grade;

        if (score < 0 || score > 100) {
            grade = "Invalid Score";
        } else {
            // Divide score by 10 to get a range indicator
            // e.g., 70-100 -> 7, 8, 9, 10
            // 60-69 -> 6
            // 50-59 -> 5
            // 45-49 -> 4 (but needs special handling for 40-44)
            // 0-39 -> 0, 1, 2, 3
            int scoreRange = score / 10;

            switch (scoreRange) {
                case 10: // Score 100
                case 9:  // Scores 90-99
                case 8:  // Scores 80-89
                case 7:  // Scores 70-79
                    grade = "A";
                    break;
                case 6:  // Scores 60-69
                    grade = "B";
                    break;
                case 5:  // Scores 50-59
                    grade = "C";
                    break;
                case 4:  // Scores 40-49
                    if (score >= 45) { // D for 45-49
                        grade = "D";
                    } else { // E for 40-44
                        grade = "E";
                    }
                    break;
                case 3:  // Scores 30-39
                case 2:  // Scores 20-29
                case 1:  // Scores 10-19
                case 0:  // Scores 0-9
                    grade = "F";
                    break;
                default:
                    grade = "Invalid Score"; // Should be caught by initial if, but good for robustness
                    break;
            }
        }

        System.out.println("The grade for score " + score + " is: " + grade);
        input.close();
    }
}