integer 的范围基于它的最大值和最小值

Question

In my class, I was asked to:

Create a method that has a parameter of a single integer and return the range of the integer parameter.

(A negative integer parameter can be treated as positive integer.)

Clarifying example:

2634982 will produce a range of 7 (since 9 minus 2)

And here's the code:

import java.util.Scanner;

public class Main {
    static int Range(int one)
    {
        int max = 0;
        int min = Integer.MAX_VALUE;
        int two = 0;
        int three = 0;

        while (one != 0) {
            two = one % 10;
            three = one / 10;
            System.out.print(two+" "+three);
            if (two > max){
                max = two;
            }
            if (two < min){
                min = two;
            }

            //System.out.print("\n"+min+" "+max);
            one = max-min;
        }
        return one;
    }

    public static void main(String[] args) {
        Scanner key = new Scanner(System.in);
        System.out.print("Enter an integer: ");
        int one = key.nextInt();
        System.out.println("\n"+one+" will produce a range of "+Range(one));
    }
}

I'm having trouble having the while loop run more than once and I feel like solving that would make this work (at least better than before)

Answer 1

Why are you using the variable "three"? I consider it isn't needed. I suggest you to use the following code:

import java.util.Scanner;
public class Main {

static int Range(int one)
{

    int max = 0;
    int min = Integer.MAX_VALUE;
    int two = 0;
    
    while (one != 0) {
        two = one % 10;
        one = one / 10;
        
        //System.out.print(two+" "+three);
    
        if (two > max){
            max = two;    
        }

        if (two < min){
            min = two;    
        }

        //System.out.print("\n"+min+" "+max);
    }
    one = max-min;    

    return one;
}

    public static void main(String[] args) {
    
        Scanner key = new Scanner(System.in);
    
        System.out.print("Enter an integer: ");
        int one = key.nextInt();
    
        System.out.println("\n"+one+" will produce a range of "+Range(one));
    
    }
}

Answer 2

An alternative solution ^†

1. Convert the int to a String .
2. Convert the String to an array of char .
3. Sort the char array (in ascending order).
4. Subtract the first array element from the last array element.

import java.util.Scanner;

public class Main {
    private static int range(int one) {
        String str = String.valueOf(one);
        str = str.replaceFirst("\\+|\\-", "");
        char[] digits = str.toCharArray();
        Arrays.sort(digits);
        return (digits[digits.length - 1] - '0') - (digits[0] - '0');
    }

    public static void main(String[] args) {
        Scanner key = new Scanner(System.in);
        System.out.print("Enter an integer: ");
        int one = key.nextInt();
        System.out.println("\n"+one+" will produce a range of "+ range(one));
    }
}

• Note that method nextInt , of class java.util.Scanner will accept integers with a leading + or - . Hence I remove that character after converting the int to a String .
• A char is really a number type (like int ) so subtracting the character 0 from the char gives its numerical value. In other words it is a way to convert a char , which is a digit, to an int .
• If you enter a single, digit int , for example 7 , the range will be 0 (zero).

Here is output from a sample run:

Enter an integer: 1959

1959 will produce a range of 8

† Assuming you are allowed to use class java.util.Arrays