I can't understand what's wrong.

//在此编写你的代码 BufferedReader reader =new BufferedReader(new InputStreamReader(System.in)); String a1=reader.readLine(); int a=Integer.parseInt(a1); if(a>0){ a=2*a; System.out.println(a); } else if(a<0){ a=a+1; System.out.println(a); } else System.out.println("0");

import java.io.*; public class Solution { public static void main(String[] args) throws Exception { //在此编写你的代码 BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String s = reader.readLine(); int i = Integer.parseInt(s); if(i > 0){ int c = i * 2; System.out.println(c); } if(i < 0){ int b = i + 1; System.out.println(b); } if(i == 0){ System.out.println(0); } } }

int b = Integer.parseInt(a);

read() gives you the ASCII value of the read number saved in an int. So if you enter 5, it's ASCII value is 53. That doubled 106 and not the expected 10. Far easier would be to use the function readLine().