public?static?void?main(String[]?args)?{
Map<Integer,?Integer>?map?=?new?HashMap<>();
Scanner?scanner?=?new?Scanner(System.in);
System.out.println("請輸入0到50範圍的數（輸入-1結束）");
int?num;
//?輸入?-1?則輸入結束
while?((num?=?scanner.nextInt())?!=?-1)?{
if?(num?<?0?||?num?>?50)?{
System.out.println(num?+?"?不在0到50範圍，請重新輸入");
continue;
}
Integer?count?=?map.get(num);
map.put(num,?count?==?null1?:?count?+?1);
}
Set<Entry<Integer,?Integer>>?entrySet?=?map.entrySet();
for?(Entry<Integer,?Integer>?entry?:?entrySet)?{
System.out.println("數字?"?+?entry.getKey()?+?"?出現了?"?+?entry.getValue()?+?"?次");
}
}
}