06. Operations Between Numbers

import java.util.Scanner;

public class OperationsBetweenNumbers {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int num1 = Integer.parseInt(scanner.nextLine());
        int num2 = Integer.parseInt(scanner.nextLine());
        String symbol = scanner.nextLine();

        String number = "";
        double sum = 0;

        if (symbol.equals("+") || symbol.equals("-") || symbol.equals("*")) {
            if (symbol.equals("+")) {
                sum = num1 + num2;
            } else if (symbol.equals("-")) {
                sum = num1 - num2;
            } else {
                sum = num1 * num2;
            }
            if (sum % 2 == 0) {
                number = "even";
            } else {
                number = "odd";
            }
            System.out.printf("%d %s %d = %d - %s\n", num1, symbol, num2, (int)sum, number);
        } else {
            if (num2 == 0) {
                System.out.printf("Cannot divide %d by zero", num1);
            } else {
                if (symbol.equals("/")) {
                    sum = (double) num1 / num2;
                    System.out.printf("%d / %d = %.2f\n", num1, num2, sum);
                } else if (symbol.equals("%")) {
                    sum = num1 % num2;
                    System.out.printf("%d %% %d = %d\n", num1, num2, (int)sum);
                }
            }
        }
    }
}

ИЛИ:

import java.io.PrintStream;
import java.util.Scanner;

public class OperationsBetweenNumbers {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int num1 = Integer.parseInt(scanner.nextLine());
        int num2 = Integer.parseInt(scanner.nextLine());
        String symbol = scanner.nextLine();

        double sum =
                symbol.equals("+") ? num1 + num2 :
                symbol.equals("-") ? num1 - num2 :
                symbol.equals("*") ? num1 * num2 :
                symbol.equals("/") && num2 != 0 ? (double) num1 / num2 :
                symbol.equals("%") && num2 != 0 ? num1 % num2 : 0;

        String number = sum % 2 == 0 ? "even" : "odd";

        if ("+-*".contains(symbol)) {
            System.out.printf("%d %s %d = %d - %s\n", num1, symbol, num2, (int)sum, number);
        } else if ("/%".contains(symbol)) {
            PrintStream printStream = num2 == 0
                    ? System.out.printf("Cannot divide %d by zero", num1)
                    : symbol.equals("/") ? System.out.printf("%d / %d = %.2f\n", num1, num2, sum)
                    : System.out.printf("%d %% %d = %d\n", num1, num2, (int) sum);
        }
    }
}