1. 9.5節提到判斷方法(predicate function)的概念，簡單來說就是許多容器類別: 如link list, queue, stack都有一個方法isEnpty()或是isFull()就是所謂的判斷方法。

2. 螞蟻書有個小優點就是美的段落的有個tips，這裡提到從安全性考量傳值呼叫的方式傳遞物件非常好，因為被呼叫的函式沒法修改原來的物件，但是大型物件的副本記憶體用量大效率差，所以用指標或參照的方式效率比較好，而傳const指標/參照可以結合兩者的優點。做法是用指向const資料的指標當參數傳入函式

• Pointer to const object
  You can modify the pointer but you can't modify the object:

const Object* object_ptr = object1;
object_ptr = object2;                // Modify pointer, OK
object_ptr->x = 40;                  // Modify object, ERROR

• Const pointer to object
  You can't modify the pointer but you can modify the object:

const Object* object_ptr = object1;
object_ptr = object2;                // Modify pointer, OK
object_ptr->x = 40;                  // Modify object, ERROR

ref :Constant pointers vs. pointer to constants in C and C++