小错误系列

package test;

public class hello {
    public static void  main(String [] argv)
    {
     char a1= '+' , a2='点' ,a3='进',a4='攻';
     char secret ='A';
     int n=2;
    while(n--!=0)   //此处不能光用n-- ,会提示没有Boolean匹配
    {
     a1 = ( char ) (a1^secret);
     a2=  ( char ) (a2^secret);
     a3=  ( char ) (a3^secret);
     a4=  ( char ) (a4^secret);
     System.out.println("密文："+a1+a2+a3+a4);
    }
    }
    
}