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1.vector对象的创建

https://en.cppreference.com/w/cpp/container/vector/vector 对象创建文档

//
// Created by 徐昌真 on 2024/11/18.
//
#include <iostream>
#include <vector>
using namespace std;void printVector(vector<int>& v){for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter) {cout << *iter << " ";}cout << endl;
}int main() {//默认构造函数vector<int> v1;cout << "默认构造函数" << ": ";printVector(v1);//初始化列表vector<int>v2_1 = {1,2,3,4,5};;  //没括号 有等号cout << "初始化列表v2_1" << ": ";printVector(v2_1);vector<int>v2_2 ({5,4,3,2,1,});  //有括号 没等号cout << "初始化列表v2_2" << ": ";printVector(v2_2);//指定size构造vector<int>v3_1 (5);cout << "指定size构造" << ": ";printVector(v3_1);vector<int>v3_2(5, 520);cout << "指定size构造" << ": ";printVector(v3_2);//迭代器传参vector<int>v4 (v2_1.begin(), v2_1.end());cout << "迭代器传参" << ": ";printVector(v4);//拷贝构造函数vector<int> v5_1 (v2_2);cout << "拷贝构造函数" << ": ";printVector(v5_1);vector<int> v5_2 (std::move(v2_1));cout << "拷贝构造函数" << ": ";printVector(v5_2);cout << "v2_1 size: " << v2_1.size() << endl;return 0;
}

输出

拷贝构造函数	类型	是否拷贝	是否移动	是否带分配器	是否 `constexpr`
`vector(const vector& other);vector（const vector& other）;`	拷贝构造函数	✅	❌	❌	❌
`vector(vector&& other);vector（vector&& other）;`	移动构造函数	❌	✅	❌	❌
`vector(const vector& other, const Allocator& alloc);`	带分配器的拷贝构造	✅	❌	✅	❌
`vector(vector&& other, const Allocator& alloc);`	带分配器的移动构造	❌	✅	✅	❌
`constexpr vector(const vector& other, const std::type_identity_t<Allocator>& alloc);`	带类型一致分配器的拷贝构造	✅	❌	✅	✅
`constexpr vector(vector&& other, const std::type_identity_t<Allocator>& alloc);`	带类型一致分配器的移动构造	❌	✅	✅	✅

2.赋值操作

https://en.cppreference.com/w/cpp/container/vector/operator%3D operator=

https://en.cppreference.com/w/cpp/container/vector/assign assign

//
// Created by 徐昌真 on 2024/11/18.
//
#include <iostream>
#include <vector>using namespace std;void printVector(vector<int>& v){for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter) {cout << *iter << ' ';}cout << endl;
}int main() {vector<int> source1 = {1,2,3,4,5};cout << "source11: " ;printVector(source1);//operator=//拷贝赋值vector<int> v1 = source1;cout << "v1: " ;printVector(v1);//移动赋值vector<int> v2 = std::move(source1);cout << "v2: " ;printVector(v2);cout << "source1 size: " << source1.size() << endl;//std::vector<T,Allocator>::assignvector<int> source2 = {1,2,3,4,5};cout << "source2: " ;printVector(source2);//自定义size初始化vector<int> v3;v3.assign(5, 520);cout << "v3: " ;printVector(v3);//迭代器初始化vector<int> v4;v4.assign(source2.begin(), source2.end());cout << "v4: " ;printVector(v4);//初始化列表vector<int> v5;v5.assign({5,4,3,2,1});cout << "v5: " ;printVector(v5);return 0;
}

3.插入操作

en.cppreference.com/w/cpp/container/vector/insert

//
// Created by 徐昌真 on 2024/11/19.
//
#include <iostream>
#include <vector>using namespace std;void printVector(vector<int>& v){for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter) {cout << *iter << ' ';}cout << endl;
}int main() {//push_backvector<int> v1;for (int i = 0; i < 10; ++i) {v1.push_back(i);}cout << "v1: ";printVector(v1);//insert_valuev1.insert(v1.begin(), 888);v1.insert(v1.begin() + 1, 666);cout << "v1: ";printVector(v1);//insert_initializerv1.insert(v1.begin() + 2, {985, 211});cout << "v1: ";printVector(v1);//insert_sizev1.insert(v1.begin(), 3, 968);cout << "v1: ";printVector(v1);//左值insertint a = 168;v1.insert(v1.begin(), a);cout << "v1: ";printVector(v1);cout << "a: " << a << endl;return 0;
}

输出

删除操作同下

sshttps://en.cppreference.com/w/cpp/container/vector/clear

https://en.cppreference.com/w/cpp/container/vector/erase

https://en.cppreference.com/w/cpp/container/vector/pop_back

//
// Created by 徐昌真 on 2024/11/19.
//
#include <iostream>
#include <vector>using namespace std;void printVector(vector<int>& v){for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter ){cout << *iter << ' ';}cout << endl;
}int main() {vector<int> v1;for (int i = 0; i < 10; ++i) {v1.push_back(i);}cout << "v1: ";printVector(v1);//clearv1.clear();cout << "size: " << v1.size() << endl;for (int i = 0; i < 10; ++i) {v1.push_back(i);}cout << "v1: ";printVector(v1);//erasev1.erase(v1.begin());cout << "v1: ";printVector(v1);v1.erase(v1.begin(), v1.begin() + 2);cout << "v1: ";printVector(v1);//pop_backv1.pop_back();cout << "v1: ";printVector(v1);return 0;
}

输出

4.扩容机制

1.5倍扩容 resize之后 capacity不会变

//
// Created by 徐昌真 on 2024/11/20.
//
#include <iostream>
#include <vector>using namespace std;void printVector(vector<int>& v){for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter ){cout << *iter << ' ';}cout << endl;
}int main() {vector<int> v;for (int i = 0; i < 10; ++i) {v.push_back(i);}cout << "v: " ;printVector(v);cout << "capacity: " << v.capacity() << endl <<  "size: " << v.size() << endl;v.resize(100);cout << "v: " ;printVector(v);cout << "capacity: " << v.capacity() << endl <<  "size: " << v.size() << endl;v.resize(5);cout << "v: " ;printVector(v);cout << "capacity: " << v.capacity() << endl <<  "size: " << v.size() << endl;return 0;
}

5.随机访问

https://en.cppreference.com/w/cpp/container/vector/operator_at

https://en.cppreference.com/w/cpp/container/vector/at

https://en.cppreference.com/w/cpp/container/vector/front

https://en.cppreference.com/w/cpp/container/vector/back

//
// Created by 徐昌真 on 2024/11/19.
//
#include <iostream>
#include <vector>using namespace std;void printVector(vector<int>& v) {for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter){cout << *iter << ' ';}cout << endl;
}int main() {vector<int> v1;for (int i = 0; i < 10; ++i) {v1.push_back(i);}cout << "v1: ";printVector(v1);//下标访问[]  不会抛出异常cout << "v1[1]: " << v1[1] << endl;cout << "v1[12]: " << v1[12] << endl;//at  //抛出异常cout << "v1.at(1): " << v1.at(1) << endl;//cout << "v1.at(12): " << v1.at(12) << endl;//front backcout << "front: " << v1.front() << endl;cout << "back: " << v1.back() << endl;return 0;
}

输出

异常抛出数组越界

6.内存交换

//
// Created by 徐昌真 on 2024/11/20.
//
#include <iostream>
#include <vector>using namespace std;void printVector(vector<int>& v, int i){cout << 'v' << i << ": ";for (vector<int>::iterator iter = v.begin(); iter != v.end(); ++iter){cout << *iter << ' ';}cout << endl;
}void printCapacity(vector<int>& v){cout << "capacity: " << v.capacity() << endl;
}int main() {//1.变量交换vector<int> v1 = {1,2,3,4,5,6,7,8,9,0};vector<int> v2 = {985, 211};printVector(v1, 1);printVector(v2, 2);cout << "----------------------------------------" << endl;v1.swap(v2);printVector(v1, 1);printVector(v2, 2);cout << "----------------------------------------" << endl;//2.缩容printCapacity(v2);v2.resize(5);printCapacity(v2);vector<int>(v2).swap(v2);  //等价于vector<int> x(v2).swap(v2);  也就是一个拷贝构造函数 x拷贝了v2的内容 capacity = size swap后 x和v1进行内存交换 后面 swap后的x内存又被清理掉printCapacity(v2);//3.清理内存cout << "----------------------------------------" << endl;v2.clear();printCapacity(v2);vector<int>(v2).swap(v2);printCapacity(v2);return 0;
}

7.空间预留

reserve修改的是capacity 避免频繁扩容交换数据

//
// Created by 徐昌真 on 2024/11/20.
//
#include <iostream>
#include <vector>using namespace std;int main() {vector<int> v1;v1.reserve(100);cout << "capacity: " << v1.capacity() << "  size: " << v1.size() << endl;return 0;
}

8.删除操作

https://en.cppreference.com/w/cpp/container/vector/clear