Java 实例 相加两个数字

public class AddTwoNumbers {

   public static void main(String[] args) {

      int num1 = 5, num2 = 15, sum;
      sum = num1 + num2;

      System.out.println("Sum of these numbers: "+sum);
   }
}

Sum of these numbers: 20

import java.util.Scanner;
public class AddTwoNumbers2 {

    public static void main(String[] args) {

        int num1, num2, sum;
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter First Number: ");
        num1 = sc.nextInt();

        System.out.println("Enter Second Number: ");
        num2 = sc.nextInt();

        sc.close();
        sum = num1 + num2;
        System.out.println("Sum of these numbers: "+sum);
    }
}

输出：

Enter First Number: 
121
Enter Second Number: 
19
Sum of these numbers: 140