java - Java中对单个输入求和和反转的方法？

Question

public static void main(String[] args) 
{
    //call for input
    System.out.println("Please Enter a 3-digit number..");
    Scanner in = new Scanner(System.in);
    int[] num = new int[3];
    int val = in.nextInt();
    for(int i = 0; i < num.length; i++);
    
    System.out.println("The Sum of the numbers is " + num[0] + num[1]+ num[2]);
    System.out.println("The Reverse of the numbers is " + num[2] + num[1]+ num[0]);
    
}

输入应该是任何大于 10 的数字，但是当我给出它时 任何数字，它都会给我相同的 000？

Answer 1

您的代码有问题:

你永远不会将用户输入放入 num 数组中，for 循环只是一个主动等待，

立即尝试:

public static void main(String[] args) 
            {
                //call for input
                System.out.println("Please Enter a 3-digit number..");
                Scanner in = new Scanner(System.in);
                int val = in.nextInt();
                int[] num = new int[3];
                if(val<=99) // is not a 3 digit number
                   return;

                int i =2;
                while (val > 0) {
                   num[i]=(val%10);
                   val = val / 10;
                   i--;
                }
                System.out.println("The Sum of the numbers is " + (num[0] + num[1]+ num[2]));
                System.out.println("The Reverse of the numbers is " + num[2] +""+ num[1]+""+ num[0]);

            }

通过输入 1 - 2 -3 可以得到:

Please Enter a 3-digit number..
1
2
3
The Sum of the numbers is 6
The Reverse of the numbers is 321