Using const

Appropriate usage of the const modifier enforces data encapsulation and protection. It is conventionally ranked in importance about as high as a mall cop, but it has far more power than a mall cop when used appropriately. Use the const modifier liberally and whenever possible. In some cases liberal use of const will bring to light some serious bugs.

Table: Using const.

Use	Do not use
void foo(const CMyStruct &ms);	void foo(CMyStruct ms);
int getProp() const;	int getProp();
const char* getName() const;	CString getName();
const CMyStruct* getStruct() const;	CMyStruct* getStruct();

If you want to allow direct access to a member variable via a function call, make two versions of the function:

1. MyStruct& GetStruct();
2. const MyStruct& GetStruct() const;

This will allow both types of access at the appropriate time such as on the left or right side of an assignment operator.