import java.util.Scanner;

class Feb25 {
	public static void main(String[] args) {
		
		// print a menu
		printMenu();
	
		Scanner kb = new Scanner(System.in);
		char choice = kb.next().charAt(0);

		System.out.printf("user entered: %c\n", choice);

		switch(choice) {
			case 'a':
				add(kb);
				break;
			case 's':
				int diff = subtract(kb);
				System.out.printf("difference: %d\n", diff);
				break;
			case 'm':
				System.out.print("Enter 2 integers separated by spaces: ");

				int val1 = kb.nextInt();
				int val2 = kb.nextInt();

				int product = multiply(val1, val2);
				System.out.printf("product: %d\n", product);
				break;	
			case 'q':
				return;
			default:
				System.out.println("Invalid choice");
		}

		System.out.println("Thank you");

	}

	// create another named block of code
	// aka another method

	static void printMenu() {
		System.out.println("a - add");
		System.out.println("s - subtract");
		System.out.println("m - multiply");
		System.out.println("q - quit");
		System.out.print("Enter choice: ");
		return;
	}
	
	static void add(Scanner scan) {
		System.out.print("Enter 2 integers separated by spaces: ");

		int val1 = scan.nextInt();
		int val2 = scan.nextInt();
		
		int sum = val1 + val2;
		System.out.printf("sum: %d\n", sum);
	}

	static int subtract(Scanner scan) {
		System.out.print("Enter 2 integers separated by spaces: ");

		int val1 = scan.nextInt();
		int val2 = scan.nextInt();
		
		int difference = val1 - val2;
		
		return difference;		
	}

	static int multiply(int arg1, int arg2) {
		int product = arg1 * arg2;
		return product;
	}
		
}