简体   繁体   中英

How can I store the scanner input integers in Java so I can print the sum of a list of input integer numbers?

I'm doing the University of Helsinki's Java MOOC and there is an exercise that asks me to create a program that lets you input as much numbers as you want, but when you input a '0' it prints the sum of all the previously input numbers and ends the program. I can't figure out how to 'store' the input numbers for calculating the sum of them when you input a '0'. The program works but inputting '0' prints '0'. This is how my code looks:

public class Application {
public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.println("Input a number.");

    while (true) {
        try {
            int number = Integer.parseInt(scanner.nextLine());
            System.out.println("Input another number.");

            if (number == 0) {
                System.out.println(number + number);
                break;
            }
        }

        catch (NumberFormatException e) {
            System.out.println("Please input a valid number.");
        }
    }
}

How can I calculate the sum of all the input numbers?

You can create a counter and make smth like this, you don't need to save all numbers:

  public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    int sum = 0;
    System.out.println("Input a number.");

    while (true) {
      try {
        int number = Integer.parseInt(scanner.nextLine());
        sum += number;
        System.out.println("Input another number.");

        if (number == 0) {
          System.out.println(sum);
          break;
        }
      }

      catch (NumberFormatException e) {
        System.out.println("Please input a valid number.");
      }
    }
 }

In line with my comment above:

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int sum = 0;
        int number = -1;

        while (number != 0) {
            try {
                System.out.print("Input a number (0 to quit): ");
                number = Integer.parseInt(scanner.nextLine());
                sum += number;
            }
            catch (NumberFormatException e) {
                System.out.println("Please input a valid number.");
            }
        }
        System.out.println("Total:" + sum);
    }

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM