java - 在方法java中将字符串转换为int

Question

所以我尝试将 int 转换为字符串，然后是 charAt(0)、charAt(1) 和 charAt(2)。我这样做是为了将 3 位整数拆分为 3 个不同的整数。然后我想将这些单独的整数转换为字符串。

我想做的是从 101 及以上获取数字并用文字打印出来。我有数百个，数十个和一个方法。我正在尝试获取第一个整数并将其应用于数百方法，第二个整数并将其应用于十位，第三个整数应用于个位方法。

这是>=101的方法

import java.util.Scanner;


public class rough {

    public static void main(String args[]) {
        int number = 0;
        Scanner scanner = new Scanner(System.in);
        System.out.print("Please type a number between 0 and 999 OR type -1 to exit:  ");
        number = scanner.nextInt();
        if (number >= 101) {
            System.out.println(hundred(first) + " AND" + tens(second) + "" + From1To19(third));
        } else {
            System.out.println("please input a number from 101: ");
        }
        //this is what i have so far(might be junk).

    public static void From101(int num) {
        String SNumber = Integer.toString(num);
        char First = SNumber.charAt(0);
        char Second = SNumber.charAt(1);
        char Third = SNumber.charAt(2);
        int num1 = Integer.parseInt(first);
    }
}

现在我尝试打印单词，但出现 3 个错误。

System.out.println(hundred(first) + " AND" + tens(second) + "" + From1To19(third));

我在 if/else 语句中添加了这一行，错误是:

 ----jGRASP exec: javac -g rough.java

rough.java:27: error: 'void' type not allowed here
                           System.out.println(hundred(first) + " AND" + tens(second) + "" + From1To19(third));
                                                     ^
rough.java:27: error: 'void' type not allowed here
                           System.out.println(hundred(first) + " AND" + tens(second) + "" + From1To19(third));
                                                             ^
rough.java:27: error: 'void' type not allowed here
                           System.out.println(hundred(first) + " AND" + tens(second) + "" + From1To19(third));
                                                                                     ^
3 errors

 ----jGRASP wedge2: exit code for process is 1.
 ----jGRASP: operation complete.

Answer 1

现在您正在将 int 转换为 String，将 String 转换为 char，以及将 char 返回到 int。

你可以跳过所有这些，直接从int -> int，使用modular division .

例如，获取12345的各个数字:

int a = 12345;
int b = a%10; //b = 5
a = a / 10; //now a = 1234
int c = a%10; //c = 4
a = a / 10; //now a = 123
int d = a%10; //d = 3
a = a / 10; //now a = 12
int e = a%10; //e = 2