具有求和功能的 For 循环

Question

我正在尝试编写一个 for 循环，该循环将接受用户输入，无论它是正数还是负数，都显示输入数字，然后显示数字的总和。我可以尽可能地显示数字，但我很难正确求和。

import java.util.Scanner;

public class DisplayandSum {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        //Variable declaration
        int size;
        int Num1;
        int count = 0;   //LCV
        int sum = 0;    //Sum of inputs
        String newNum;  // Declared string for user input         
        System.out.println("Please enter an integers and press enter.");

        newNum = input.next();

        Num1 = Integer.parseInt(newNum);

        size = newNum.length();

        System.out.print("These are your numbers: ");

        if (Num1 > 0) //If number is positive
        {
            for (count = 0; count <= (size - 1); count++) {
                System.out.print(newNum.charAt(count) + "");
            }
        } else if (Num1 < 0) // If number is negative
        {
            System.out.print("-");

            for (Num1 = 1; Num1 <= (size - 1); count++) {
                System.out.print(newNum.charAt(count) + "");
            }
        }
        if (Num1 > 0) //If positive sum
        {
            for (count = 0; count < (size - 1); count++) {
                sum = sum + count;
            }

        } else if (Num1 < 0) // If negative sum 
        {
            for (Num1 = size; Num1 > 2; Num1--) {
                Num1 = Math.abs(Num1);
            }
            sum = sum + Num1 % 10;
            Num1 = Num1 / 10;
        }

        sum = sum + (0 - Num1);

        System.out.println("\nand the sum of your digits is: " + sum);

    }
}

Answer 1

当您说“数字之和”时，我假设您实际上是指“数字之和”？

您的代码比它需要的更复杂。

// Variable declaration
int sum = 0;    //Sum of inputs
String newNum;  // Declared string for user input         

System.out.println("Please enter an integer and press enter.");
newNum = input.next();

size = newNum.length();

System.out.print("These are your numbers: ");

for (count = 0; count < size; count++)
{
   char  ch = newNum.charAt(count);
   if (Character.isDigit(ch) {
      System.out.print(ch);
      sum += (ch - '0');
   }
}

System.out.println("\nand the sum of your digits is: " + sum);