我一直得到一个"别无错误"的错误

Question

我正在尝试编写一些代码,使用户输入有效的用户名,他们会尝试三次.每次我编译它时,如果我有一个else if语句,我得到一个没有if的错误.

  Scanner in = new Scanner(System.in);

  String validName = "thomsondw";

  System.out.print("Please enter a valid username: ");
  String input1 = in.next();

  if (input1.equals(validName))
  {
    System.out.println("Ok you made it through username check");
  }
  else
  {
    String input2 = in.next(); 
  }
  else if (input2.equals(validName))
  {
    System.out.println("Ok you made it through username check");
  }
  else
  {
    String input3 = in.next();
  }
  else if (input3.equals(validName))
  {
    System.out.println("Ok you made it through username check");
  }
  else
  {
    return;
  }

Answer 1

你误解了使用 if-else

if(condition){
  //condition is true here
}else{
  //otherwise
}else if{
  // error cause it could never be reach this condition
}

阅读更多if-then和if-then-else语句

你可以有

if(condition){

}else if (anotherCondition){

}else{
  //otherwise means  'condition' is false and 'anotherCondition' is false too
}