1.大一剛學C++，遇到了點問題，如有不妥的地方還望指教。
2.實例化類別模板的成員函數，函數結束後為什麼會自動呼叫析構函數？ 例如

~set()
{
    cout<<"destory!"<<endl;
}
private:
    int size;
    T *p;

void set<T>::intersection(set s2) //交集
int cnt = 0;
int size2 = s2.size;
sort(p, p + size);
sort(s2.p, s2.p + size2);
int MaxSize = max(size, size2);
T *tmp = new T[MaxSize];

if (MaxSize == size)//集合A含元素个数大于B
    for (int i = 0; i<MaxSize; i++)
        if (s2.b_search(p[i])) //二分查找
            tmp[cnt++] = p[i];

else if (size != size2)
    for (int i = 0; i<MaxSize; i++)
        if (b_search(s2.p[i]))
            tmp[cnt++] = s2.p[i];

for (int i = 0; i<cnt - 1; i++)
    cout << tmp[i] << "，";
cout << tmp[cnt - 1];

這樣的話
int a2[] = { 2,4,1,6,0 };
int a4[] = { 2,4,6,8 ,9 };
set<int> t2(a2, 5);
set<int> t4(a4, 5);
#呼叫t2.intersection(t4); 時最後會顯示destory!為什麼析構函式呼叫的那麼早？此時如果在析構函數中加上delete []p 還會報錯@_@