Một sự thay đổi có thể chấp nhận được nếu tất cả các dòng mã bị ảnh hưởng bởi nó có thể được thay đổi, nếu cần thiết, và mã xây dựng lại chống lại những thay đổi. Trong thực tế, điều này thường có nghĩa là thay đổi phải được hạn chế bên trong của một thành phần chứ không phải là API công cộng của nó. | Simpo PDF Merge and Split Unregistered Version - http do not have constructors and never have destructors. Once a T class is publicly defined it is often difficult to make client-compatible changes to it. Summary A change is acceptable if every line of code affected by it can be altered where necessary and the code rebuilt against the changes. In effect this often means that a change must be restricted to the internals of a component rather than its public API. For this reason you should endeavor to keep private definitions and header files and anything else which is likely to be subject to change out of the public domain. A change is also acceptable if it can be verified as compatible according to the guidelines I ve discussed here. In general the key compatibility issue for shared library DLLs is backward binary compatibility with source compatibility an additional aim. These guidelines derive from those used within Symbian in accordance with the C standard. I am very grateful to David Batchelor John Forrest and Andrew Thoelke of Symbian who have previously written guides to compatibility best practice on Symbian OS which I used as the basis of this chapter. Simpo PDF Merge and Split Unregistered Version - http 19 Thin Templates Now now my good man this is no time to be making enemies Voltaire on his deathbed in response to a priest who asked him to renounce Satan C templates are useful for code that can be reused with different types for example to implement container classes such as dynamic arrays. Templates allow the code to be generic accepting any type without forcing the programmer to overload a function. template class T class CDynamicArray public CBase public . Functions omitted for clarity void Add const T aEntry T operator TInt aIndex Prior to the introduction of templates to the C standard generic code tended to be written using void arguments to allow the caller to specify any pointer type as an argument. However
