帮我看看这段程序有什么不对
public class lianxi{public static void main(string[] args){
System.out.println(6>5>4);
System.out.println(3==3==3);
System.out.println(true & flase);
int a;
System.out.println(a=20);
int a;
System.out.println((a=20)=30);
System.out.println(""+1+2+3+4);
System.out.println(""+(1+2+3+4));
System.out.println((int)true);
System.out.println(sizeof(long));
System.out.println((int)true);
System.out.println((double)(10/3));
}
}