[计算机科学经

Size i elemsi draw draw c templates

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Unformatted text preview: nst& env) { typename T::Index i; middle<T>(i); } class Client { public: typedef int Index; }; Client main_client; int main() { shell(main_client); } C++ Templates - The Complete Guide 6 78 實際運用 Templates 這個例子展現軟體開發㆗的㆒種典型分層方式:高層的 function templates(例如 shell())倚賴 其他部份(例如 middle())完成,它們都用到了提供基本設施的函式(例如 core())。當我 們具現化 shell()時,它的所有㆘層函式也都會被具現化。本例之㆗,最深層的 core()以 int 型別具現化(這是由於 middle()以 Client::Index 型別具現化的緣故),卻試圖從該型別㆗ 提領(dereference)數值,這麼做是錯誤的。良好的㆒般性診斷訊息會包含「引發錯誤」的每㆒ 層呼叫軌跡,但我們的觀察是,這麼多訊息反而沒有多大用處。 你可以在 [StroustrupDnE] 找到㆒段非常好的論述,圍繞著此問題的核心思想。Bjarne Stroustrup 在討論㆗給出兩種辦...
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This note was uploaded on 08/25/2012 for the course EECS 101 taught by Professor Wre during the Fall '12 term at Beacon FL.

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