C++ list用法
创建一个list实例并赋值：
1 // 创建实例以及赋值 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 //第一种，通过构造函数 7 int myints[] = {75,23,65,42,13}; 8 list<int> mylist1(myints, myints+5); 9 list<int> mylist2(2,100); // 2个值为100的元素 10 //第二种，用push_back，或push_front 11 for (int i = 1; i <= 5; ++i) mylist1.push_back(i); 12 mylist2.push_front (200); 13 mylist2.push_front (300); 14 //第三种,用assign 15 list<int> first; 16 list<int> second; 17 first.assign(7,100); // 给first添加7个值为100的元素 18 second.assign(first.begin(), first.end()); // 复制first给second 19 int myints[] = {16, 8, 4}; 20 first.assign (myints, myints + 3); // 将数组myints的内容添加给first 21 22 //第四种，见insert函数 23 return 0; 24 }
成员函数：
Iterator: （可用于遍历list）
iterator begin(); //返回指向第一个元素的迭代器
iterator end(); //返回指向最后一个元素的迭代器
reverse_iterator rbegin(); //返回指向第一个元素的逆向迭代器
reverse_rend(); //返回指向最后一个元素的逆向迭代器
1 //list的遍历 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 int myints[] = {75,23,65,42,13}; 7 list<int> mylist (myints,myints+5); 8 cout << "mylist contains:"; 9 //这是正序输出： 10 for (list<int>::iterator it = mylist.begin(); it != mylist.end(); ++it) 11 cout << ' ' << *it; 12 cout << '\n'; 13 14 list.clear(); 15 //逆序输出： 16 for (int i = 1; i <= 5; ++i) mylist.push_back(i); 17 cout << "mylist backwards:"; 18 for (list<int>::reverse_iterator rit = mylist.rbegin(); rit != mylist.rend(); ++rit) 19 cout << ' ' << *rit; 20 cout << '\n'; 21 return 0; 22 } 输出结果为： mylist contains: 75 23 65 42 13 mylist backwards: 5 4 3 2 1
Capacity: （用于获取list容器大小信息）
bool empty() const; //list为空时返回true
size_type size() const; //返回list容器里元素的个数
size_type max_size() const; //返回list容器最大能容纳的元素的个数，主要用于调用list的resize()函数时，检查所请求的size大小是否被允许
Element access:（用于获取首尾元素）
reference front(); //返回第一个元素的引用
const_reference front() const;
reference back(); //返回最后一个元素的引用
const_reference front() const;
Modifiers:
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asign //给容器添加新内容：
template<class InputIterator>
void assign(InputIterator first, InputIterator last); //first,last是一个序列中起始和结束的迭代器的值，[first, last)包含了序列中所有元素
void assign(size_type n, const value_type& val); //给list赋值n个值为val的元素
1 // list::assign 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> first; 7 list<int> second; 8 first.assign(7,100); // 给first添加7个值为100的元素 9 second.assign(first.begin(), first.end()); // 复制first给second 10 11 int myints[] = {16, 8, 4}; 12 first.assign (myints, myints + 3); // 将数组myints的内容添加给first 13 14 cout << "Size of first: " << int (first.size()) << '\n'; 15 cout << "Size of second: " << int (second.size()) << '\n'; 16 return 0; 17 } 输出结果为： Size of first: 3 Size of second: 7
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push_front, pop_front, push_back, pop_back
void push_front(const value_type& val); //在list头添加元素
void pop_front(); //删除list头的元素
void push_back(const value_type& val); //在list尾添加元素
void pop_back(); //删除list尾的元素
1 #include <iostream> 2 #include <list> 3 using namespace std; 4 int main () { 5 list<int> mylist (2,100); // 2个值为100的元素 6 // list::push_front 7 mylist.push_front (200); 8 mylist.push_front (300); 9 10 cout << "mylist contains:"; 11 for (list<int>::iterator it = mylist.begin(); it != mylist.end(); ++it) 12 cout << ' ' << *it; 13 cout << '\n'; 14 15 // list::pop_front 16 cout << "Popping out the elements in mylist:"; 17 while (!mylist.empty()) { 18 cout << ' ' << mylist.front(); 19 mylist.pop_front(); 20 } 21 cout << "\nFinal size of mylist is " << mylist.size() << '\n'; 22 23 // list::push_back 24 int myint; 25 cout << "Please enter some integers (enter 0 to end):\n"; 26 do { 27 cin >> myint; 28 mylist.push_back (myint); 29 } while (myint); 30 cout << "mylist contains:"; 31 for (list<int>::iterator it = mylist.begin(); it != mylist.end(); ++it) 32 cout << ' ' << *it; 33 cout << '\n'; 34 35 // list::pop_back 36 while (!mylist.empty()) { 37 cout << ' ' << mylist.back(); 38 mylist.pop_back(); 39 } 40 cout << "\nFinal size of mylist is " << mylist.size() << '\n'; 41 42 return 0; 43 } 输出结果： mylist contai: 300 200 100 100 Popping out the elements in mylist: 300 200 100 100 Final size of mylist is 0 Please enter some integers (enter 0 to end): 56 23 8 5 6 0 mylist contains: 56 23 8 5 6 0 0 6 5 8 23 56 Final size of mylist is 0
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insert //插入元素：
iterator insert (iterator position, const value_type& val); //position是要插入的这个list的迭代器，val是要插入的值
void insert (iterator position, size_type n, const value_type& val); //从该list容器中的position位置处开始，插入n个值为val的元素
template <class InputIterator>
void insert (iterator position, InputIterator first, InputIterator last); //first，last是我们选择的把值插入到这个list中的值所在的容器的迭代器
1 // inserting into a list 2 #include <iostream> 3 #include <list> 4 #include <vector> 5 using namespace std; 6 int main () { 7 list<int> mylist; 8 list<int>::iterator it; 9 // 初始化 10 for (int i = 1; i <= 5; ++i) mylist.push_back(i); // 1 2 3 4 5 11 it = mylist.begin(); 12 ++it; // 迭代器it现在指向数字2 ^ 13 //在i0t指向的位置出插入元素10 14 mylist.insert (it,10); // 1 10 2 3 4 5 15 16 // "it" 仍然指向数字2 ^ 17 //在it指向的位置出插入两个元素20 18 mylist.insert (it,2,20); // 1 10 20 20 2 3 4 5 19 20 --it; // 现在it指向数字20 ^ 21 22 vector<int> myvector (2,30); //创建vector容器，并初始化为含有2个值为30的元素 23 //将vector容器的值插入list中 24 mylist.insert (it,myvector.begin(),myvector.end()); 25 // 1 10 20 30 30 20 2 3 4 5 26 //it仍然指向数字20 // ^ 27 cout << "mylist contains:"; 28 for (it = mylist.begin(); it != mylist.end(); ++it) 29 cout << ' ' << *it; 30 cout << '\n'; 31 32 return 0; 33 } 输出结果： mylist contains: 1 10 20 30 30 20 2 3 4 5
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erase //删除元素：
iterator erase (iterator position); //删除迭代器position指向的值，也可以不用变量接收其返回值
iterator erase (iterator first, iterator last); //删除[first, last)中的值，也可以不用变量接收其返回值
1 // erasing from list 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> mylist; 7 list<int>::iterator it1,it2; 8 9 // set some values: 10 for (int i = 1; i < 10; ++i) mylist.push_back(i*10); 11 12 // 10 20 30 40 50 60 70 80 90 13 it1 = it2 = mylist.begin(); // ^^ 14 advance (it2,6); // ^ ^ 15 ++it1; // ^ ^ 16 17 it1 = mylist.erase (it1); // 10 30 40 50 60 70 80 90 18 // ^ ^ 19 20 it2 = mylist.erase (it2); // 10 30 40 50 60 80 90 21 // ^ ^ 22 23 ++it1; // ^ ^ 24 --it2; // ^ ^ 25 //没有变量接收其返回值 26 mylist.erase (it1,it2); // 10 30 60 80 90 27 // ^ 28 cout << "*it1 : " << *it1 << endl; 29 cout << "mylist contains:"; 30 for (it1 = mylist.begin(); it1 != mylist.end(); ++it1) 31 cout << ' ' << *it1; 32 cout << '\n'; 33 34 return 0; 35 } 输出结果： it1 : 40 mylist contains: 10 30 60 80 90
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swap //交换两个list的内容
void swap(list& x); //要交换的两个列表的存储的元素的类型必须是一样的，列表大小可以不同
1 // swap lists 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> first (3,100); // 三个值为100的元素 7 list<int> second (5,200); // 五个值为200的元素 8 9 first.swap(second); 10 11 cout << "first contains:"; 12 for (list<int>::iterator it = first.begin(); it != first.end(); it++) 13 cout << ' ' << *it; 14 cout << '\n'; 15 16 cout << "second contains:"; 17 for (list<int>::iterator it = second.begin(); it != second.end(); it++) 18 cout << ' ' << *it; 19 cout << '\n'; 20 21 return 0; 22 } 输出结果： first contains: 200 200 200 200 200 second contains: 100 100 100
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resize //调整list大小
void resize (size_type n, value_type val = value_type()); //将list大小调整为能容纳n个元素，若n大于当前list大小，则会从list末尾一直插入val值，直到list大小满足n;
1 // resizing list 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> mylist; 7 8 // 初始化 9 for (int i = 1; i < 10; ++i) mylist.push_back(i); 10 11 mylist.resize(5); 12 mylist.resize(8,100); 13 mylist.resize(12); 14 15 cout << "mylist contains:"; 16 for (list<int>::iterator it = mylist.begin(); it != mylist.end(); ++it) 17 cout << ' ' << *it; 18 cout << '\n'; 19 20 return 0; 21 } 输出结果： mylist contains: 1 2 3 4 5 100 100 100 0 0 0 0
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clear //清空list
void clear(); //删除list的所有元素
1 // clearing lists 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> mylist; 7 list<int>::iterator it; 8 9 mylist.push_back (100); 10 mylist.push_back (200); 11 mylist.push_back (300); 12 13 cout << "mylist contains:"; 14 for (it = mylist.begin(); it != mylist.end(); ++it) 15 cout << ' ' << *it; 16 cout << '\n'; 17 18 mylist.clear(); 19 mylist.push_back (1101); 20 mylist.push_back (2202); 21 22 cout << "mylist contains:"; 23 for (it = mylist.begin(); it != mylist.end(); ++it) 24 cout << ' ' << *it; 25 cout << '\n'; 26 27 return 0; 28 } 输出结果： mylist contains: 100 200 300 mylist contains: 1101 2202
Operations:
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splice //将一个list中的值移到另一个list中
void splice (iterator position, list& x); //将列表x中的所有元素移到当前list中，从当前列表的position指向的位置开始，此时列表x为空
void splice (iterator position, list& x, iterator i); //将列表x中迭代器 i 指向的元素移到当前list的position指向的位置处，由于i指向的元素从列表x中被移除，所以迭代器 i 此时是invalid的；position是当前列表的迭代器，i是列表x的迭代器
void splice (iterator position, list& x, iterator first, iterator last); //将列表x中[first, last)的元素移到当前list中，从position指向的位置开始；first, last是列表x的迭代器
1 // splicing lists 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> mylist1, mylist2; 7 list<int>::iterator it; 8 9 // 初始化 10 for (int i = 1; i <= 4; ++i) 11 mylist1.push_back(i); // mylist1: 1 2 3 4 12 13 for (int i = 1; i <= 3; ++i) 14 mylist2.push_back(i*10); // mylist2: 10 20 30 15 16 it = mylist1.begin(); 17 ++it; // 指向数字2 18 19 mylist1.splice (it, mylist2); // mylist1: 1 10 20 30 2 3 4 20 // mylist2 (empty) 21 // "it" 仍然指向数字2 22 23 mylist2.splice (mylist2.begin(),mylist1, it); 24 // mylist1: 1 10 20 30 3 4 25 // mylist2: 2 26 // "it" 此时已经无效了 27 it = mylist1.begin(); 28 advance(it,3); // "it" 指向数字30 29 30 mylist1.splice ( mylist1.begin(), mylist1, it, mylist1.end()); 31 // mylist1: 30 3 4 1 10 20 32 33 cout << "mylist1 contains:"; 34 for (it = mylist1.begin(); it != mylist1.end(); ++it) 35 cout << ' ' << *it; 36 cout << '\n'; 37 38 cout << "mylist2 contains:"; 39 for (it = mylist2.begin(); it != mylist2.end(); ++it) 40 cout << ' ' << *it; 41 cout << '\n'; 42 43 return 0; 44 } 输出结果： mylist1 contains: 30 3 4 1 10 20 mylist2 contains: 2
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remove //删除list中特定的值
void remove (const value_type& val); //从list中删除所有值为val的元素
1 // remove from list 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 int myints[]= {17, 89, 7, 89, 14}; 7 list<int> mylist (myints,myints+5); 8 9 mylist.remove(89); 10 11 cout << "mylist contains:"; 12 for (list<int>::iterator it = mylist.begin(); it != mylist.end(); ++it) 13 cout << ' ' << *it; 14 cout << '\n'; 15 16 return 0; 17 } 输出结果： mylist contains: 17 7 14
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remove_if //按条件删除
template <class Predicate>
void remove_if (Predicate pred)； //pred可以是一个函数，也可以是一个class，但它需要有一个参数，且参数类型跟list中存储元素类型相同，满足条件就返回true
1 // list::remove_if 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 // a predicate implemented as a function: 6 bool single_digit (const int& value) { return (value < 10); } 7 8 // a predicate implemented as a class: 9 struct is_odd { 10 //重载操作符 () 11 bool operator() (const int& value) { return (value % 2) == 1; } 12 }; 13 14 int main () { 15 int myints[] = {15, 36, 7, 17, 20, 39, 4, 1}; 16 list<int> mylist (myints, myints + 8); // 15 36 7 17 20 39 4 1 17 18 mylist.remove_if (single_digit); // 15 36 17 20 39 19 20 mylist.remove_if (is_odd()); // 36 20 21 22 cout << "mylist contains:"; 23 for (std::list<int>::iterator it=mylist.begin(); it!=mylist.end(); ++it) 24 cout << ' ' << *it; 25 cout << '\n'; 26 27 return 0; 28 } 输出结果： mylist contains: 36 20
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unique //删除重复值
void unique(); //只能删除相邻的重复元素，然后保留第一个值，因此这个函数只对排好序的list有用
template <class BinaryPredicate>
void unique (BinaryPredicate binary_pred); //binary_pred可以是函数，也可以是class，但它需要有两个参数，且类型跟list中存储的值类型相同，满足某个条件就返回true
1 // list::unique 2 #include <iostream> 3 #include <cmath> 4 #include <list> 5 using namespace std; 6 // a binary predicate implemented as a function: 7 bool same_integral_part (double first, double second) { return ( int(first)==int(second) ); } 8 9 // a binary predicate implemented as a class: 10 struct is_near { 11 bool operator() (double first, double second) { return (fabs(first-second)<5.0); } 12 }; 13 14 int main () { 15 double mydoubles[] = { 12.15, 2.72, 73.0, 12.77, 3.14, 16 12.77, 73.35, 72.25, 15.3, 72.25 }; 17 list<double> mylist (mydoubles,mydoubles+10); 18 cout << "mylist contains:"; 19 for (list<double>::iterator it = mylist.begin(); it != mylist.end(); ++it) 20 cout << ' ' << *it; 21 cout << '\n'; 22 23 mylist.unique(); 24 cout << "mylist contains:"; 25 for (list<double>::iterator it = mylist.begin(); it != mylist.end(); ++it) 26 cout << ' ' << *it; 27 cout << '\n'; 28 29 mylist.sort(); // 2.72, 3.14, 12.15, 12.77, 12.77, 30 // 15.3, 72.25, 72.25, 73.0, 73.35 31 32 mylist.unique(); // 2.72, 3.14, 12.15, 12.77 33 // 15.3, 72.25, 73.0, 73.35 34 cout << "mylist contains:"; 35 for (list<double>::iterator it = mylist.begin(); it != mylist.end(); ++it) 36 cout << ' ' << *it; 37 cout << '\n'; 38 39 mylist.unique (same_integral_part); // 2.72, 3.14, 12.15 40 // 15.3, 72.25, 73.0 41 cout << "mylist contains:"; 42 for (list<double>::iterator it = mylist.begin(); it != mylist.end(); ++it) 43 cout << ' ' << *it; 44 cout << '\n'; 45 46 mylist.unique (is_near()); // 2.72, 12.15, 72.25 47 48 cout << "mylist contains:"; 49 for (list<double>::iterator it = mylist.begin(); it != mylist.end(); ++it) 50 cout << ' ' << *it; 51 cout << '\n'; 52 53 return 0; 54 } 输出结果： mylist contains: 12.15 2.72 73 12.77 3.14 12.77 73.35 72.25 15.3 72.25 mylist contains: 12.15 2.72 73 12.77 3.14 12.77 73.35 72.25 15.3 72.25 mylist contains: 2.72 3.14 12.15 12.77 15.3 72.25 73 73.35 mylist contains: 2.72 3.14 12.15 15.3 72.25 73 mylist contains: 2.72 12.15 72.25
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merge //合并有序的list
void merge(list &x); //会将列表x中的元素按默认的顺序移入当前列表当中，此时列表x为空，当前列表仍为有序列表
template<class Compare>
void merge (list& x, Compare comp); //comp可以为一个函数，要求有两个参数且参数类型跟list中存储的元素类型相同，当满足条件时返回true，merge就按照这个条件将两个列表合并
1 // list::merge 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 // compare only integral part: 6 bool mycomparison (double first, double second) { return ( (first)<(second) ); } 7 8 int main () { 9 list<double> first, second; 10 11 first.push_back (3.1); 12 first.push_back (2.2); 13 first.push_back (2.9); 14 15 second.push_back (3.7); 16 second.push_back (7.1); 17 second.push_back (1.4); 18 19 first.sort(); 20 second.sort(); 21 22 first.merge(second); 23 cout << "first contains:"; 24 for (list<double>::iterator it = first.begin(); it != first.end(); ++it) 25 cout << ' ' << *it; 26 cout << '\n'; 27 // (second 现在为空) 28 29 second.push_back (2.1); 30 second.push_back(2.5); 31 32 first.merge(second,mycomparison); 33 cout << "first contains:"; 34 for (list<double>::iterator it = first.begin(); it != first.end(); ++it) 35 cout << ' ' << *it; 36 cout << '\n'; 37 38 return 0; 39 } 输出结果： first contains: 1.4 2.2 2.9 3.1 3.7 7.1 first contains: 1.4 2.1 2.2 2.5 2.9 3.1 3.7 7.1
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sort //排序
void sort(); //默认升序排列
template <class Compare>
void sort (Compare comp); //comp可以是一个函数，要求有两个参数，类型跟list中元素类型相同，满足条件时返回true，sort()函数就按照comp中制定的规则对元素进行排序
1 // list::sort 2 #include <iostream> 3 #include <list> 4 #include <string> 5 #include <cctype> 6 using namespace std; 7 // comparison, not case sensitive. 8 bool compare_nocase (const string& first, const string& second) { 9 unsigned int i = 0; 10 while ((i < first.length()) && (i < second.length()) ) { 11 //将大写字母转为小写字母 12 if (tolower(first[i]) < tolower(second[i])) return true; 13 else if (tolower(first[i]) > tolower(second[i])) return false; 14 ++i; 15 } 16 return ( first.length() < second.length() ); 17 } 18 19 int main () { 20 list<string> mylist; 21 list<string>::iterator it; 22 mylist.push_back ("one"); 23 mylist.push_back ("two"); 24 mylist.push_back ("Three"); 25 26 mylist.sort(); 27 28 cout << "mylist contains:"; 29 for (it = mylist.begin(); it != mylist.end(); ++it) 30 cout << ' ' << *it; 31 cout << '\n'; 32 33 mylist.sort(compare_nocase); 34 35 cout << "mylist contains:"; 36 for (it = mylist.begin(); it != mylist.end(); ++it) 37 cout << ' ' << *it; 38 cout << '\n'; 39 40 return 0; 41 } 输出结果： mylist contains: Three one two mylist contains: one Three two
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reverse //逆序：
void reverse(); //将list中元素的顺序逆转过来
1 // reversing list 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> mylist; 7 8 for (int i = 1; i < 10; ++i) mylist.push_back(i); 9 10 mylist.reverse(); 11 12 cout << "mylist contains:"; 13 for (list<int>::iterator it = mylist.begin(); it != mylist.end(); ++it) 14 cout << ' ' << *it; 15 cout << '\n'; 16 17 return 0; 18 } 输出结果： mylist contains: 9 8 7 6 5 4 3 2 1
Observers:
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get_allocator //返回一个跟该list有关的分配器对象
allocator_type get_allocator() const; //可以用来给数组动态分配空间
1 // list::get_allocator 2 #include <iostream> 3 #include <list> 4 using namespace std; 5 int main () { 6 list<int> mylist; 7 int * p; 8 9 // allocate an array of 5 elements using mylist's allocator: 10 p = mylist.get_allocator().allocate(5); 11 12 // assign some values to array 13 for (int i = 0; i < 5; ++i) p[i] = i; 14 15 cout << "The allocated array contains:"; 16 for (int i = 0; i < 5; ++i) cout << ' ' << p[i]; 17 cout << '\n'; 18 19 mylist.get_allocator().deallocate(p,5); 20 21 return 0; 22 } 输出结果： The allocated array contains: 9 8 7 6 5 4 3 2 1