java数字代码

Question

我有一个问题，让我告诉在给定的数字位数。我插入了条件语句，但无论插入什么数字，它都会给我“九”位数。代码如下。我是一名数学专业的学生，不是计算机科学专业的学生，所以我觉得我没有使用最有效的方法

import java.util.Scanner;

public class E52 {
    public static void main(String[] args) {
        // part 1: import scanner
        Scanner sc = new Scanner(System.in);

        // part 2: ask user for a number
        System.out.println("Please enter a number: ");
        int number = sc.nextInt();

        // part 3: tell how many digits are in each number by using string and conditional statements
        String number1Str;
        if (number >= 0 || number <= 10) number1Str = "one";
        if (number >= 10 || number <= 100) number1Str = "two";
        if (number >= 100 || number <= 1000) number1Str= "three";
        if (number >= 1000 || number <= 10000) number1Str = "four";
        if (number >= 10000 || number <= 100000) number1Str = "five";
        if (number >= 100000 || number <= 1000000) number1Str = "six";
        if (number >= 1000000 || number <= 10000000) number1Str = "seven";
        if (number >= 10000000 || number <= 100000000) number1Str = "eight";
        if (number >= 100000000 || number <= 1000000000) number1Str = "nine";
        else number1Str = "undefined";

        System.out.println("There are " + number1Str + " digits in the given number.");

        sc.close();
    }
}

Answer 1

创建一个数组，然后获取输入的长度并选择，让它选择条目，这会容易得多：

Scanner sc = new Scanner(System.in);

// part 2: ask user for a number
System.out.println("Please enter a number: ");
Integer number = sc.nextInt();
final String[] numNames = {
            "",
            "one",
            "two",
            "three",
            "four",
            "five",
            "six",
            "seven",
            "eight",
            "nine",
            "ten",
            "eleven",
            "twelve",
            "thirteen",
            "fourteen",
            "fifteen",
            "sixteen",
            "seventeen",
            "eighteen",
            "nineteen"
    };
System.out.println(numNames[number.toString().length()]);

Answer 2

这将给你数字计数，无论数字有多大或多小。虽然有一些角落的情况可能会失败的代码，但我仍然觉得这将是有用的，你在其他方面

public class CountNum {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String numAsString = sc.nextLine();
        System.out.println(numAsString.length());
        sc.close();
    }

}