C++学习笔记(字符串string、vector_deque、queue,multiset、map、multimap、容器拷贝问题)(复制粘贴,方便后面翻阅)
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2022-04-12 21:13:47
1.string操作
#include
#include
#include //算法
using namespace std;
//STL standa...
1.string操作
#include #include #include //算法 using namespace std; //STL standard template libary 标准模(mu)板库 C++一部分,编译器自带 //Android NDK支持 //java.lang java.util包中API,java的一部分 //string初始化 void main() { //string由c字符串衍生过来的 string s1 = "craig david"; string s2("7 days"); string s3 = s2; string s4(10,'a'); cout << s4 << endl; system("pause"); } //string遍历 void main() { string s1 = "craig david"; // ^ //1 数组方式 for (int i = 0; i < s1.length(); i++) { cout << s1[i] << endl; } //2 迭代器指针 for (string::iterator it = s1.begin(); it != s1.end(); it++) { cout << *it << " "; } cout << endl; //3 at函数(charAt) // 可能会抛出异常 try { for (int i = 0; i < s1.length() + 3; i++) { cout << s1.at(i) << " "; } } catch (...) { cout << "异常" << endl; } system("pause"); } //string字符串->c字符串转换 void main() { //string -> char* string s1 = "walking away"; const char* c = s1.c_str(); printf("%s\n",c); // string s2 = c; //string->char[] //从string中赋值字符到char[] char arr[50] = {0}; s1.copy(arr,4,0); cout << arr << endl; system("pause"); } //字符串拼接 void main() { string s1 = "alan"; string s2 = "jackson"; //1. string s3 = s1 + s2; string s4 = " pray"; //2. s3.append(s4); cout << s3 << endl; system("pause"); } //字符串查找替换 void main() { string s1 = "apple google apple iphone"; //从0开始查找"google"的位置 int idx = s1.find("google", 0); cout << idx << endl; //统计apple出现的次数 int idx_app = s1.find("apple",0); //npos大于任何有效下标的值 int num = 0; while (idx_app != string::npos) { num++; cout << "找到的索引:" << idx_app << endl; idx_app+=5; idx_app = s1.find("apple", idx_app); } cout << num << endl; system("pause"); } void main() { string s1 = "apple google apple iphone"; //0-5(不包含5)替换为jobs s1.replace(0, 5, "jobs"); cout << s1 << endl; //所有apple替换为jobs int idx = s1.find("apple", 0); while (idx != string::npos) { s1.replace(idx, 5, "jobs"); idx += 5; idx = s1.find("apple", idx); } cout << s1 << endl; system("pause"); } //删除(截取)和插入 void main() { string s1 = "apple google apple iphone"; //删除a,找到a所在的指针 string::iterator it = find(s1.begin(),s1.end(),'g'); //只能删除一个字符 s1.erase(it); //开头末尾插入字符串 s1.insert(0, "macos"); s1.insert(s1.length(), " facebook"); cout << s1 << endl; system("pause"); } //java StringBuffer才可变 //String 不可变 //大小写转换 void main() { string s1 = "JASON"; //原始字符串的起始地址,原始字符串的结束地址, 目标字符串的起始地址, 函数名称 transform(s1.begin(), s1.end()-1,s1.begin(), tolower); cout << s1 << endl; transform(s1.begin(), s1.end() - 1, s1.begin(), toupper); cout << s1 << endl; system("pause"); }
2.容器vector
//容器 //Vector //初始化 #include void printVector(vector &v) { //通过数组的方式遍历 for (int i = 0; i < v.size(); i++) { cout << v[i] << endl; } } void main() { //1. vector v1; v1.push_back(20); v1.push_back(40); v1.push_back(15); v1.push_back(7); //2. vector v2 = v1; //3.部分复制 vector v3(v1.begin(),v1.begin()+2); printVector(v3); system("pause"); } //添加 删除 void main() { //添加到结尾 vector v1; v1.push_back(20); v1.push_back(40); v1.push_back(15); v1.push_back(7); //访问头部 v1.front() = 11; //访问尾部 v1.back() = 90; //删除结尾的元素 //v1.pop_back(); while (v1.size() > 0) { cout << "末尾的元素:" << v1.back() << endl; v1.pop_back(); } printVector(v1); system("pause"); } //数组的方式 void main() { vector v1; v1.push_back(20); v1.push_back(40); v1.push_back(15); v1.push_back(7); v1[2] = v1[2] +10; //容器等价于动态数组 vector v2(10); for (int i = 0; i < v2.size(); i++) { v2[i] = i + 1; } printVector(v2); system("pause"); } //迭代器遍历 //迭代器的种类(正向,反向迭代器) void main() { vector v1; v1.push_back(20); v1.push_back(40); v1.push_back(15); v1.push_back(7); //正向 for (vector::iterator it = v1.begin(); it < v1.end(); it++) { cout << *it << endl; } cout << "-----------------" << endl; //反向迭代 for (vector::reverse_iterator it = v1.rbegin(); it < v1.rend(); it++) { cout << *it << endl; } system("pause"); } //删除 void main() { vector v1(10); for (int i = 0; i < v1.size(); i++) { v1[i] = i + 1; } //删除指定位置 vector::iterator it = v1.begin(); it += 3; v1.erase(it); //distance(v1.begin(), it); //删除区间 v1.erase(v1.begin(), v1.begin() + 3); for (vector::iterator it = v1.begin(); it < v1.end(); it++) { if (*it == 5) { printf("%x\n", it); vector::iterator tmp = v1.erase(it); //注意以后开发中编译器版本问题 printf("%x,%x\n",it,tmp); } } //插入 v1.insert(v1.begin() + 2, 100); v1.insert(v1.end() - 1, 200); printVector(v1); system("pause"); }
3.队列deque
//双向队列 #include void printDeque(deque& q) { for (int i = 0; i < q.size(); i++) { cout << q[i] << endl; } } void main() { deque d1; //添加到尾部 d1.push_back(2); d1.push_back(10); //添加到头部 d1.push_front(-90); d1.push_front(-30); //printDeque(d1); //cout << d1.front() << endl; //cout << d1.back() << endl; //两个方向弹出 //d1.pop_back(); //d1.pop_front(); printDeque(d1); //查找第一个-90元素索引位置,无需遍历 deque::iterator it = find(d1.begin(),d1.end(),-90); if (it != d1.end()) { int idx = distance(d1.begin(), it); cout << "索引位置为:" << idx << endl; } system("pause"); } //队列(没有迭代器) /* void main() { queue q; q.push(78); q.push(18); q.push(20); q.push(33); //q.front(); //q.back(); while (!q.empty()) { int tmp = q.front(); cout << tmp << endl; q.pop(); } system("pause"); } */ //优先级队列 /* #include void main() { //默认 最大值优先级 priority_queue pq1; pq1.push(12); pq1.push(3); pq1.push(40); pq1.push(15); while (!pq1.empty()) { int tmp = pq1.top(); cout << tmp << endl; pq1.pop(); } cout << "----------" << endl; //最小值优先级队列 priority_queue,greater> pq2; pq2.push(12); pq2.push(3); pq2.push(40); pq2.push(15); while (!pq2.empty()) { int tmp = pq2.top(); cout << tmp << endl; pq2.pop(); } system("pause"); } */
4.栈stack
//栈 /* #include void main() { stack s; for (int i = 0; i < 10; i++) { s.push(i+1); } while (!s.empty()) { int tmp = s.top(); cout << tmp << endl; s.pop(); } system("pause"); } */
5.集合list,set,map
//list #include void printList(list& lst) { //迭代器 //没有重载“<”运算符 for (list::iterator it = lst.begin(); it != lst.end(); it++) { cout << *it << endl; } } //基本操作 /* void main() { list lst; for (int i = 0; i < 10; i++) { //尾部插入元素 lst.push_back(i); } //头部插入元素 lst.push_front(80); lst.push_front(90); list::iterator it = lst.begin(); it++; cout << *it << endl; //it = it + 3; 注意:不支持随机访问 printList(lst); system("pause"); } */ //删除 /* void main() { list lst; for (int i = 0; i < 10; i++) { //尾部插入元素 lst.push_back(i); } list::iterator it = lst.begin(); //删除 it++; //删除第二个元素 //lst.erase(it); //删除区间(已经被删除了元素不能再删除) list::iterator it_begin = lst.begin(); list::iterator it_end = lst.begin(); it_end++; it_end++; it_end++; lst.erase(it_begin, it_end); //直接根据内容删除元素 lst.remove(5); printList(lst); system("pause"); } */ //list插入(应用:频繁的修改) //vector(应用:随机访问v[100]) /* void main() { list lst; for (int i = 0; i < 10; i++) { //尾部插入元素 lst.push_back(i); } list::iterator it = lst.begin(); it++; lst.insert(it, 100); printList(lst); system("pause"); } */ //set 元素唯一 默认从小到大 #include void printSet(set &s) { for (set::iterator it = s.begin(); it != s.end(); it++) { cout << *it << endl; } } /* void main() { set s; //添加元素 for (int i = 0; i < 10; i++) { s.insert(i+1); } s.insert(20); s.insert(15); s.insert(15); //删除 set::iterator it = s.begin(); it++; s.erase(it); printSet(s); system("pause"); } */ //元素按照从大到小排列 /* #include void main() { //同Java中:Map> set> s; s.insert(10); s.insert(5); s.insert(20); s.insert(99); for (set>::iterator it = s.begin(); it != s.end(); it++) { cout << *it << endl; } system("pause"); } */ //元素类型为Teacher对象,按照年龄排序 /* class Teacher { public: Teacher(char* name, int age) { this->name = name; this->age = age; } void print() { cout << name << "," << age << endl; } public: char* name; int age; }; //自定义排序规则 //仿函数 struct MyAgeSorter { bool operator()(const Teacher &left, const Teacher &right) { return left.age < right.age; } }; void main() { set s; s.insert(Teacher("jack",18)); s.insert(Teacher("rose", 20)); s.insert(Teacher("jason", 22)); s.insert(Teacher("alan", 5)); //s.insert(Teacher("jimy", 5)); //不会插入 for (set::iterator it = s.begin(); it != s.end(); it++) { cout << (*it).name << "," << (*it).age << endl; } system("pause"); } */ //set查找 /* void main() { set s; //添加元素 for (int i = 0; i < 10; i++) { s.insert(i + 1); } //printSet(s); //等于4的元素指针 set::iterator s_4 = s.lower_bound(4); //cout << *s_4 << endl; //大于4的元素指针 set::iterator s_5 = s.upper_bound(4); //cout << *s_5 << endl; //一次性获取等于4的元素指针,和大于4的元素指针\ //BasicNameValuePair pair::iterator, set::iterator> p = s.equal_range(4); cout << *p.first << endl; cout << *p.second << endl; system("pause"); } */ //multiset 允许重复的元素 /* void main() { multiset s; s.insert(2); s.insert(8); s.insert(2); s.insert(8); for (multiset::iterator it = s.begin(); it != s.end(); it++) { cout << *it << endl; } system("pause"); } */ //map添加元素的方式 #include #include /* void main() { //key -> value //1. map map1; map1.insert(pair(1,"jack")); map1.insert(pair(2, "rose")); //2 map1.insert(make_pair(3,"jason")); //3 map1.insert(map::value_type(4,"alan")); //4 map1[5] = "jimmy"; //map["NO1"] = 90; //前三种方式,如果key已经存在,重复添加会报错 //第四种方式,如果key已经存在,重复添加会覆盖 //遍历输出 for (map::iterator it = map1.begin(); it != map1.end(); it++) { cout << it->first << "," << it->second << endl; } system("pause"); } */ void printMap(map &map1) { for (map::iterator it = map1.begin(); it != map1.end(); it++) { cout << it->first << "," << it->second << endl; } } //删除 /* void main() { map map1; map1.insert(pair(1, "jack")); map1.insert(pair(2, "rose")); map1.insert(pair(3, "jason")); map::iterator it = map1.begin(); it++; map1.erase(it); printMap(map1); system("pause"); } */ //添加的结果 /* void main() { map map1; map1.insert(pair(1, "jack")); map1.insert(pair(2, "rose")); map1.insert(pair(3, "jason")); //获取添加的结果(first元素指针,second 是否成功) pair::iterator, bool> res = map1.insert(pair(3, "alan")); if (res.second) { cout << "添加成功" << endl; } else { cout << "添加失败" << endl; } printMap(map1); system("pause"); } */ //查找 /* void main() { map map1; map1.insert(pair(1, "jack")); map1.insert(pair(2, "rose")); map1.insert(pair(3, "jason")); printMap(map1); cout << "---------" << endl; //获取key等于大于5的元素的值 pair::iterator, map::iterator> p = map1.equal_range(2); if (p.first != map1.end()){ //等于2的元素key value cout << p.first->first << p.first->second << endl; //大于2的元素key value cout << p.second->first << p.second->second << endl; } system("pause"); } */ //一个key对应多个value //一个部门多个员工 //multimap /* class Employee { public: Employee(char* name,int age) { this->name = name; this->age = age; } public: char* name; int age; }; void main() { multimap map1; //开发部 map1.insert(make_pair("开发", Employee("搁浅", 20))); map1.insert(make_pair("开发", Employee("彪哥", 20))); //财务 map1.insert(make_pair("财务", Employee("小颖", 16))); map1.insert(make_pair("财务", Employee("rose", 20))); //销售 map1.insert(make_pair("销售", Employee("阿呆", 30))); map1.insert(make_pair("销售", Employee("呵呵", 30))); //遍历输出 for (multimap::iterator it = map1.begin(); it != map1.end(); it++) { cout << it->first << "," << it->second.name << "," << it->second.age << endl; } cout << "----------------" << endl; //只获取“财务”部的员工 //获取“财务部”员工的个数,key对应的value的个数 int num = map1.count("财务"); multimap::iterator it = map1.find("财务"); int c = 0; //控制循环的次数 while (it != map1.end() && c < num) { cout << it->first << "," << it->second.name << "," << it->second.age << endl; it++; c++; } system("pause"); } */ //深拷贝与浅拷贝 /* class Employee { public: //构造函数 Employee(char* name, int age) { this->name = new char[strlen(name) + 1]; strcpy(this->name, name); this->age = age; } //析构函数 ~Employee() { if (this->name != NULL) { delete[] this->name; this->name = NULL; this->age = 0; } } //拷贝构造函数 //Employee e = Employee(const Employee &obj) { this->name = new char[strlen(obj.name) + 1]; strcpy(this->name, obj.name); this->age = obj.age; } //重载= //e1 = e2; Employee& operator=(const Employee &obj) { //释放旧的内存 if (this->name != NULL) { delete[] this->name; this->name = NULL; this->age = 0; } //重新分配 this->name = new char[strlen(obj.name) + 1]; strcpy(this->name, obj.name); this->age = obj.age; return *this; } public: char* name; int age; }; void func() { vector v1; Employee e1("jack",20); v1.push_back(e1); } void main() { //vector v1; //Employee e1("jack",20); //将e1拷贝到vector中 //v1.push_back(e1); func(); system("pause"); } */