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STL vector常用API
1、容器:序列容器(时间决定)、关联式容器(容器中的数据有一定规则)
2、迭代器:通过迭代器寻找、遍历容器中的数据
vetor的使用:数据遍历与输出
#define _CRT_SECURE_NO_WARNINGS #include<iostream> #include<vector> //向量 动态数组 #include<algorithm> //算法头文件 #include<string> using namespace std; void myPrint(int val){ cout << val << " "; } //1. STL中的容器算法迭代器 void test01(){ //容器 vector<int> v; v.push_back(10); v.push_back(20); v.push_back(30); v.push_back(40); v.push_back(50); //获得开始迭代器 vector<int>::iterator begin = v.begin(); //获得结束位置迭代器 vector<int>::iterator end = v.end(); //遍历算法 for_each(begin, end, myPrint); cout << endl; } //2. 容器可以存放对象 class Person{ friend ostream& operator<<(ostream& out, Person &person); public: Person(string name,int age){ this->mName = name; this->mAge = age; } public: string mName; int mAge; }; ostream& operator<<(ostream& out, Person &person){ out << "Name:" << person.mName << " Age:" << person.mAge << endl; return out; } void test02(){ vector<Person> v; //在向容器中插入元素的时候,一定要保证元素能够被拷贝。 v.push_back(Person("aaa", 10)); v.push_back(Person("bbb", 20)); v.push_back(Person("ccc", 30)); v.push_back(Person("ddd", 40)); v.push_back(Person("eee", 50)); vector<Person>::iterator begin = v.begin(); vector<Person>::iterator end = v.end(); while (begin != end){ cout << (*begin); ++begin; } } //3. 存放对象指针 void test03(){ vector<Person *> v; //创建数据 Person *p1 = new Person("aaa", 10); Person *p2 = new Person("bbb", 20); Person *p3 = new Person("ccc", 30); Person *p4 = new Person("ddd", 40); Person *p5 = new Person("eee", 50); v.push_back(p1); v.push_back(p2); v.push_back(p3); v.push_back(p4); v.push_back(p5); vector<Person *>::iterator begin = v.begin(); vector<Person *>::iterator end = v.end(); while (begin != end){ cout << (*begin)->mName << " " << (*begin)->mAge << endl; ++begin; } delete p5; delete p4; delete p3; delete p2; delete p1; } //4. 容器可以嵌套容器 void test04(){ vector<vector<int>> vs; vector<int> v1; vector<int> v2; vector<int> v3; vector<int> v4; vector<int> v5; for (int i = 0; i < 5;i ++){ v1.push_back(i + 10); v2.push_back(i + 20); v3.push_back(i + 30); v4.push_back(i + 40); v5.push_back(i + 50); } vs.push_back(v1); vs.push_back(v2); vs.push_back(v3); vs.push_back(v4); vs.push_back(v5); vector<vector<int>>::iterator begin = vs.begin(); vector<vector<int>>::iterator end = vs.end(); while (begin != end){ vector<int>::iterator sbegin = (*begin).begin(); vector<int>::iterator send = (*begin).end(); while (sbegin != send){ cout << *sbegin << " "; ++sbegin; } cout << endl; ++begin; } cout << "-------------------" << endl; for (vector<vector<int>>::iterator it = vs.begin(); it != vs.end(); ++it){ for (vector<int>::iterator sit = it->begin(); sit != it->end(); ++sit){ cout << *sit << " "; } cout << endl; } } int main(){ //test01(); //test02(); //test03(); test04(); system("pause"); return EXIT_SUCCESS; }
Vector常用API
#define _CRT_SECURE_NO_WARNINGS #include<iostream> #include<vector> using namespace std; void printVector(const vector<int> &vec){ for (vector<int>::const_iterator it = vec.begin(); it != vec.end(); ++it){ cout << *it << " "; } cout << endl; } void printReverseVector(vector<int> &vec){ for (vector<int>::reverse_iterator it = vec.rbegin(); it != vec.rend(); ++it){ cout << *it << " "; } cout << endl; } //1. vector构造 /* vector<T> v; //采用模板实现类实现,默认构造函数 vector(v.begin(), v.end());//将v[begin(), end())区间中的元素拷贝给本身。 vector(n, elem);//构造函数将n个elem拷贝给本身。 vector(const vector &vec);//拷贝构造函数。 //例子 使用第二个构造函数 我们可以... int arr[] = {2,3,4,1,9}; vector<int> v1(arr, arr + sizeof(arr) / sizeof(int)); */ void test01(){ int arr[] = { 2, 3, 4, 1, 9 }; vector<int> v(arr,arr+ sizeof(arr)/sizeof(int)); printVector(v); printReverseVector(v); vector<int> v2(10, 6); printVector(v2); } //2. vector常用赋值操作 /* assign(beg, end);//将[beg, end)区间中的数据拷贝赋值给本身。 assign(n, elem);//将n个elem拷贝赋值给本身。 vector& operator=(const vector &vec);//重载等号操作符 swap(vec);// 将vec与本身的元素互换。 */ void test02(){ vector<int> v; v.assign(10, 6); vector<int> v2; v2.push_back(1); v2.push_back(2); v2.push_back(3); printVector(v); printVector(v2); cout << "-----------------" << endl; v.swap(v2); printVector(v); printVector(v2); //v.assign(v2.begin(),v2.end()); //printVector(v); } //3. 大小操作 /* size();//返回容器中元素的个数 empty();//判断容器是否为空 resize(int num);//重新指定容器的长度为num,若容器变长,则以默认值填充新位置。如果容器变短,则末尾超出容器长度的元素被删除。 resize(int num, elem);//重新指定容器的长度为num,若容器变长,则以elem值填充新位置。如果容器变短,则末尾超出容器长>度的元素被删除。 capacity();//容器的容量 reserve(int len);//容器预留len个元素长度,预留位置不初始化,元素不可访问。 */ void test03(){ //1. resize开辟空间,并且初始化 //2. reserve只开辟空间,没有初始化 vector<int> v2; v2.push_back(1); v2.push_back(2); v2.push_back(3); cout << "size:" << v2.size() << endl; v2.resize(5); //改变容器中元素的个数,多余的扔掉 cout << "size:" << v2.size() << endl; printVector(v2); v2.reserve(20); //预留空间 v2.push_back(10); printVector(v2); cout << "size:" << v2.size() << endl; } void test04(){ vector<int> v; v.resize(5); v.push_back(10); cout << "capacity:" << v.capacity() << endl; cout << "size:" << v.size() << endl; cout << "----------" << endl; vector<int> v2; v2.reserve(5); v2.push_back(10); cout << "capacity:" << v2.capacity() << endl; cout << "size:" << v2.size() << endl; //cout << v2[2] << endl; } void test05(){ vector<int> v; v.reserve(100000); int *p = NULL; int count = 0; for (int i = 0; i < 100000;i ++){ v.push_back(i); if (p != &v[0]){ p = &v[0]; count++; } } cout << count << endl; } //swap用法 void test06(){ vector<int> v; for (int i = 0; i < 100000; i++){ v.push_back(i); } cout << "容量:" << v.capacity() << endl; cout << "大小:" << v.size() << endl; cout << "---------------" << endl; v.resize(10); cout << "容量:" << v.capacity() << endl; cout << "大小:" << v.size() << endl; cout << "---------------" << endl; vector<int>(v).swap(v); cout << "容量:" << v.capacity() << endl; cout << "大小:" << v.size() << endl; } //7. vector数据存取操作 /* at(int idx); //返回索引idx所指的数据,如果idx越界,抛出out_of_range异常。 operator[];//返回索引idx所指的数据,越界时,运行直接报错 front();//返回容器中第一个数据元素 back();//返回容器中最后一个数据元素 */ void test07(){ vector<int> v; v.push_back(1); v.push_back(2); v.push_back(3); cout << v.front() << endl; cout << v.back() << endl; v.front() = 100; v.back() = 200; for (int i = 0; i < v.size(); i ++){ cout << v[i] << " "; } cout << endl; } //8. vector插入删除 /* insert(const_iterator pos, int count,ele);//迭代器指向位置pos插入count个元素ele. push_back(ele); //尾部插入元素ele pop_back();//删除最后一个元素 erase(const_iterator start, const_iterator end);//删除迭代器从start到end之间的元素 erase(const_iterator pos);//删除迭代器指向的元素 clear();//删除容器中所有元素 */ void test08(){ vector<int> v; v.push_back(10); v.push_back(20); v.push_back(30); v.push_back(40); v.insert(v.begin()+2,100); printVector(v); v.pop_back(); printVector(v); v.erase(v.begin()); printVector(v); v.erase(v.begin(),v.end()); cout << "size:" << v.size() << endl; } int main(){ //test01(); //test02(); //test03(); //test04(); //test05(); //test06(); //test07(); test08(); system("pause"); return EXIT_SUCCESS; }
STL vector常用API
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