STL(標準模板庫)是C++標準庫的重要組成部分,包含容器、迭代器和算法三大核心組件。1. 容器如vector、map、set用于存儲數(shù)據(jù);2. 迭代器用于訪問容器元素;3. 算法如sort、find用于操作數(shù)據(jù)。選擇容器時,vector適合動態(tài)數(shù)組,list適合頻繁插入刪除,deque支持雙端快速操作,map/unordered_map用于鍵值對查找,set/unordered_set用于去重。使用算法時應(yīng)包含<algorithm>頭文件,并配合迭代器和lambda表達式。注意避免失效迭代器、刪除時更新迭代器、不可修改map/set的key值,或使用范圍for循環(huán)提高安全性。掌握STL能顯著提升代碼效率與可讀性。
如果你剛開始學(xué) C++,可能已經(jīng)聽說過 STL 這個詞。它全稱是 Standard Template Library(標準模板庫),是 C++ 中非常強大的一部分,提供了一系列通用的數(shù)據(jù)結(jié)構(gòu)和算法。這篇文章不會從頭講語法,而是直接帶你了解 STL 的核心組成、如何使用常見容器和算法,并給出一些實用建議。

什么是 STL,為什么重要?
STL 是 C++ 標準庫的一部分,主要包含三個核心組件:容器(Containers)、迭代器(Iterators) 和 算法(Algorithms)。它們共同作用,讓你可以高效地處理數(shù)據(jù)。

- 容器用來存儲數(shù)據(jù),比如
vector
、map
、set
。 - 迭代器像指針一樣用來訪問容器中的元素。
- 算法則是對這些數(shù)據(jù)進行操作的函數(shù),例如排序、查找等。
用 STL 的好處在于你不用自己實現(xiàn)鏈表、動態(tài)數(shù)組這些基礎(chǔ)結(jié)構(gòu),而且代碼會更簡潔、可讀性更高。
常見容器怎么選?看需求
C++ 提供了多種容器類型,每種適用于不同場景。以下是最常用的幾個:

-
vector
:動態(tài)數(shù)組,適合順序訪問,尾部插入/刪除快。 -
list
:雙向鏈表,適合頻繁在中間插入或刪除元素。 -
deque
:雙端隊列,支持兩端快速插入。 -
map
/unordered_map
:鍵值對集合,前者基于紅黑樹有序,后者基于哈希無序但更快。 -
set
/unordered_set
:集合類型,用于去重,同理有有序和無序之分。
舉個例子,如果你需要一個列表,隨時添加元素又不確定大小,首選 vector
;如果要根據(jù)關(guān)鍵字快速查找,就用 map
或 unordered_map
。
小提示:盡量避免用
vector<bool>
,這個特化版本行為跟普通 vector 不太一樣,容易踩坑。
算法怎么用?別自己造輪子
STL 提供了大量的算法函數(shù),都在 <algorithm>
頭文件里。常見的如:
-
sort()
:排序 -
find()
:查找元素 -
copy()
:復(fù)制數(shù)據(jù) -
transform()
:轉(zhuǎn)換數(shù)據(jù)
這些函數(shù)通常接受兩個迭代器作為參數(shù),表示操作范圍。例如:
#include <algorithm> #include <vector> std::vector<int> v = {5, 2, 8, 1}; std::sort(v.begin(), v.end()); // 排序后變成 {1, 2, 5, 8}
你可以配合 lambda 表達式來自定義排序規(guī)則或者判斷條件,這樣寫出來的代碼既簡潔又靈活。
注意:有些算法返回的是迭代器而不是索引,使用前記得檢查是否合法(比如
find()
找不到時返回end()
)。
使用迭代器時要注意什么?
迭代器是連接容器和算法的橋梁,但在使用過程中有幾個地方容易出錯:
- 避免使用已經(jīng)失效的迭代器。例如你在遍歷
vector
時進行了擴容操作(比如push_back
),可能會導(dǎo)致迭代器失效。 - 刪除元素時注意更新迭代器。例如使用
list.erase(it++)
是一種常見做法。 - 在使用
map
或set
時,不要嘗試修改 key 的值,因為這會影響內(nèi)部結(jié)構(gòu)。
如果你不太確定迭代器的行為,可以用范圍 for 循環(huán)來簡化操作,比如:
for (const auto& item : my_vector) { std::cout << item << std::endl; }
這種方式更直觀,也更安全。
基本上就這些。STL 是 C++ 編程中不可或缺的一部分,掌握好常用容器和算法,能讓你寫出更清晰、高效的代碼。雖然一開始可能會覺得有點抽象,但多用幾次就能上手了。
The above is the detailed content of C tutorial on the Standard Template Library (STL). For more information, please follow other related articles on the PHP Chinese website!

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