Main.java:1: 错误: 需要class, interface或enum
Scanner scan = new Scanner(System.in);
^
Main.java:2: 错误: 需要class, interface或enum
int a = scan.nextInt();
^
Main.java:3: 错误: 需要class, interface或enum
int b = scan.nextInt();
^
Main.java:4: 错误: 需要class, interface或enum
return a b;
^
4 个错误