测试错题积累

 

 

 

 

 

 

代码:

public static void main(String[] args) {
// TODO Auto-generated method stub
Scanner input=new Scanner(System.in);
String s1 ="hello";
s1.concat("everyone");
int index =s1.indexOf("y");
System.out.println(index);
}
}

 

 

 

 

代码:

运行结果: