import java.util.HashSet
import java.util.Iterator
import java.util.Random
public class Set {
public static void main(String[] args) {
// HashSet
HashSet<String> hs = new HashSet<String>()
hs.add("a")
hs.add("b")
hs.add("n")
hs.add("1")
System.out.println(hs)
// 遍历
Iterator it = hs.iterator()
while (it.hasNext()) {
System.out.println(it.next())
}
System.out.println("--------------")
//foreach
for (String str : hs) {
System.out.println(str)
}
System.out.println("------------------")
Random R =new Random()
HashSet<Integer> hs1 = new HashSet<Integer>()
while(hs1.size()<10){
int res = R.nextInt(20)+1
hs1.add(res)
}
System.out.println(hs1)
}
}