java - 如何处理以下代码中的运行时错误？我正在编写一个代码来查找java中数字的第一位数字

Question

import java.util.*;
import java.io.*;

public class Main {
  public static void main(String args[]) throws IOException {

    //write your code here
    Scanner sc = new Scanner(System.in);
    int t;
    t = sc.nextInt();
    while (t!=0){
      int a;
      a = sc.nextInt();
      while (a>10)
        a/=10;

        System.out.println(+a);
    }
  }
}

Answer 1

如果你只想处理异常，你必须用 try/catch block 包围它。如果您想查找数字的第一位，请使用以下代码:

import java.util.*;

public class Main {
public static void main(String args[]){

    try {
        Scanner sc = new Scanner(System.in);
        System.out.println("Enter number: ");
        int number = sc.nextInt();
        boolean state = true;
        while (state) {
            if ((number >= 10) || (number <= -10)) {
                number /= 10;
            } else {
                if (number < 0) {
                    number *= -1;
                    System.out.println(number);
                    state = false;
                } else {
                    System.out.println(number);
                    state = false;
                }
            }
        }
    } catch (InputMismatchException e){
        System.out.println("Your input doest match");
    }
}
}