c++7模板和STL.ppt

模板与标准模板库 代码重用的另一种方式 模板类7 1模板的基本知识一个模板类至少具有一个类参数 类参数是个符号以表示将要被某个确定数据类型代替的类型 classintArray public int private int a intsize intArray foremphasisintdummy val arbitraryvalue int constint 模板类方式 templateclassArray public T templateT templateconstT templateArray Array ints a newT size s templateArray Array delete a templateostream 7 1 1模板实例 includeusingnamespacestd declarationoftemplateclassArrayintmain Arraya1 100 arrayof100doublesa1 6 3 14 cout a1 6 endl 例子 templateclassArray Arraya0 50 Arraya1 50 templateArraya2 50 Arraya3 50 7 1 2参数表中的模板类模板类可以作为一种数据类型出现在参数表中 templateostream 7 2函数模板templateTMax Tt intn inti 0 Ttemp t 0 for i 1 i n i if temp t i temp t i returntemp templatevoidswap T 7 3标准模板库STL标准模板库 STL 是标准C 库的一部分 7 3 1容器 算法和迭代器STL容器 vectorstackqueuedequelistsetmap等STL算法 copysortsearchmergepermute等STL提供了多种类型的迭代器 可分别进行正向 反向 双向和随机遍历操作 7 3 2STL的优越性 intsq int voidmain vectorv 10 fillupvwithvalue for inti 0 i 10 i v push back i for each v begin v end sq intsq inta returna a include include includeusingnamespacestd voidmain vectorv 10 dequed sort v beging v end sort d begin d end 7 3 3容器基础知识STL基本容器可以分为两组 序列式容器和关联式容器 序列式容器如同数组 可以通过下标来访问 listvectordeque 关联式容器中的元素可以通过键值 key 来访问 关联式容器可以将任意类型的数据作为键值来使用 mapmultimapsetmultiset floatgnp m China include includeintmain usingnamespacestd vector iteratorv1 Iter v2 Iter v3 Iter v4 Iter v5 Iter Createanemptyvectorv0vectorv0 Createavectorv1with3elementsofdefaultvalue0vectorv1 3 Createavectorv2with5elementsofvalue2vectorv2 5 2 Createacopy vectorv4 ofvectorv2vectorv4 v2 vectorv5 v4 begin 1 v4 begin 3 cout v1 for v1 Iter v1 begin v1 Iter v1 end v1 Iter cout v1 Iter cout endl cout v2 for v2 Iter v2 begin v2 Iter v2 end v2 Iter cout v2 Iter cout endl cout v4 for v4 Iter v4 begin v4 Iter v4 end v4 Iter cout v4 Iter cout endl cout v5 for v5 Iter v5 begin v5 Iter v5 end v5 Iter cout v5 Iter cout endl 7 3 4基本序列式容器 vector deque和list include includeusingnamespacestd intmain inti vectornums nums insert nums begin 999 nums insert nums begin 15 nums insert nums end 60 for i 0 i nums size i cout nums i endl 15 99960cout endl nums erase nums begin 99960nums erase nums begin 60for i 0 i nums size i cout nums i endl 60return0 include include includeusingnamespacestd voiddump list names reverse cout include includeusingnamespacestd intmain vectorc1 vector iteratorc1 Iter vector const iteratorc1 cIter c1 push back 1 c1 push back 2 c1 Iter c1 begin cout Thefirstelementofc1is c1 Iter endl c1 Iter 20 c1 Iter c1 begin cout Thefirstelementofc1isnow c1 Iter endl Thefollowinglinewouldbeanerrorbecause iteratorisconstc1 cIter c1 begin c1 cIter 200 7 3 5vector deque和list的效率比较7 3 6基本关联式容器 set multiset map和multimap include includeusingnamespacestd intmain sets s insert 999 s insert 18 s insert 321 s insert 999 set const iteratorit it s begin while it s end cout key it s find key if it s end cout key isnotinset endl elsecout key isinset endl return0 include include includeusingnamespacestd intmain mapm m zero 0 m one 1 m two 2 m three 3 m four 4 m five 5 m six 6 m seven 7 m eight 8 m nine 9 cout m three endl m five endl m seven endl return0 7 3 7容器适配器容器适配器是基本容器的衍生物 并利用基本容器来实现其特定的功能 容器适配器有三种 stack queue和priority queue 默认情况下STLstack衍生自dequestacks stack s 如果要改变成vector的衍生 则用如下方式 stack s include include includeusingnamespacestd intmain conststringprompt Enteranalgebraicexpression constcharlParen constcharrParen stacks stringbuf cout prompt endl getline cin buf for inti 0 i buf length i if isspace buf i s push buf i cout Originalexpression buf endl cout Expressioninreverse while s empty chart s top s pop if t lparen t rParen elseif t rParen t lParen cout t cout endl return0 include includeusingnamespacestd intmain queueq queque intj 1 for inti 0 i 6 i q push j j 2 while q empty cout q front endl returnintegerq pop returnvoid return0 include include include include includeusingnamespacestd intmain constintHOW MANY 8 inti priority queuenums srand time NULL for i 0 i HOW MANY i intnext rand cout next endl nums push next cout n Prioritybyvalue endl for i 0 i HOW MANY i cout nums top endl nums pop return0 7 3 8其他容器 string include include includeusingnamespacestd voidprintChar charc cout c intmain strings pele thegreatestever cout s s endl cout sinreverse for each s rbegin s rend printChar cout endl char where find s begin s end a cout a isthe where s begin 1 thcharin s endl random shuffle s begin s end cout safterarandomshuffle s endl where find s begin s end a cout a isthe where s begin 1 thcharin s endl sort s begin s end cout ssortedinascendingorder s endl return0 7 3 9STL算法排序和搜索 数值处理 集合运算 复制等 include include include includeusingnamespacestd voiddump inti couti2 intmain vectorv 10 generate v begin v end rand replace if v begin v end odd 0 sort v begin v end comp for each v begin v end dump return0 include includeusingnamespacestd voidprint constchar char int intmain constintLEN 27 constintMED LEN 2 charalph abcdefghijklmnopqrstuvwxyz print n nOriginalarray n alph LEN random shuffle alph alph LEN print Afterrandom shuffle n alph LEN nth element alph alph MED alph LEN print n nAfternth element n alph LEN print n tmedian alph MED 1 LEN 2 cout cout 7 3 10其他STL构件函数对象 functionobject 函数适配器 functionadaptor STLallocator 7 4异常处理voidg try f catch intx 整型异常被抛出的处理 catch chars 字符型的异常被抛出的处理 例strings intindex len while true cout index len try s erase index len catch out of range cou