vector容器

一、简介：

vector容器是一个单端容器，形式如下，

 

这是一个在std名字空间中定义的模板类：

namespace std
{
template <class T, class Allocator = allocator<T> >
class vector;
}

如果使用vector必须包含头文件<vector>。

二、vector类的操作：

1、创建、复制和销毁

void test01(void)
{
    vector<int> v1;
    cout << "v1 size: " << v1.size() << endl;
    showVector(v1);
    v1.push_back(10);
    v1.push_back(20);
    cout << "v1 size: " << v1.size() << endl;
    showVector(v1);

    vector<int> v2(v1);
    showVector(v2);
    vector<int> v3(2);
    showVector(v3);
    vector<int> v4(10, 2);
    showVector(v4);
    vector<int> v5(v4.begin(), v4.end());
    showVector(v5);

}

结果：

2、无修改操作：

void test02()
{
    vector<int> v1;
    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    v1.push_back(40);
    v1.push_back(50);
    showVector(v1);
    cout << "v1.size: " << v1.size() << endl;
    cout << "v1.empty: " << v1.empty() << endl;
    cout << "v1.max_size: " << v1.max_size() << endl;
    cout << "v1.capacity: " << v1.capacity() << endl;
    v1.reserve(10);
    showVector(v1);
    cout << "v1.size: " << v1.size() << endl;
    cout << "v1.capacity: " << v1.capacity() << endl;

    vector<int> v2;
    vector<int> v3;
    v2.push_back(1);
    v2.push_back(2);
    v2.push_back(3);
    v3.push_back(1);
    v3.push_back(2);
    v3.push_back(3);
    v3.push_back(4);

    cout << "v2 > v3 ? ===" << (v2 > v3) << endl;
    cout << "v2 > v3 ? ===" << (v2 < v3) << endl;
    cout << "v2 > v3 ? ==="  << (v2 >= v3) << endl;
    cout << "v2 > v3 ? ===" << (v2 <= v3) << endl;
    cout << "v2 > v3 ? ===" << (v2 == v3) << endl;
    cout << "v2 > v3 ? ==="  << (v2 != v3) << endl;
}

结果：

3、赋值：

void test03()
{
    vector<int> v1;
    vector<int> v2;

    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    v2.push_back(1);
    v2.push_back(2);
    v2.push_back(3);
    showVector(v1);
    showVector(v2);
    v1.assign(10, 44);
    showVector(v1);
    v2.assign(v1.begin(), v1.end());
    showVector(v2);
    v1.push_back(123);
    showVector(v1);
    v1.swap(v2);
    showVector(v1);
    showVector(v2);

    swap(v1, v2);
    showVector(v1);
    showVector(v2);

    vector<int> v3;
    showVector(v3);
    v3 = v2;
    showVector(v3);
}

结果：

4、元素访问：

void test04(void)
{
    vector<int> v1;
    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    v1.push_back(40);
    showVector(v1);
    cout << v1.at(2) << endl;
    cout << v1[2] << endl;
    cout << v1.front() << endl;
    cout << v1.back() << endl;
}

结果：

5、迭代器操作：

void test05(void)
{
    vector<int> v1;
    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    v1.push_back(40);
    v1.push_back(50);
    v1.push_back(60);

    for (vector<int>::iterator it = v1.begin(); it != v1.end(); it++)
    {
        cout << (*it) << " ";
    }
    cout << endl;

    for (vector<int>::reverse_iterator it = v1.rbegin(); it != v1.rend(); it++)
    {
        cout << (*it) << " ";
    }
    cout << endl;
}

结果：

 

 

 

 

 6、插入和删除元素：

void test06()
{
    vector<int> v1;
    v1.push_back(10);
    v1.push_back(20);
    v1.push_back(30);
    v1.push_back(40);
    showVector(v1);
    v1.insert(v1.begin() + 1, 23);
    showVector(v1);

    v1.insert(v1.begin() + 2, 10, 33);
    showVector(v1);
    vector<int> v2;
    v2.push_back(1);
    v2.push_back(2);
    v1.insert(v1.begin(), v2.begin(), v2.end());
    showVector(v1);
    v1.pop_back();
    showVector(v1);
    v1.erase(v1.begin());
    showVector(v1);
    v1.erase(v1.begin() + 1, v1.end() - 1);
    showVector(v1);
    v1.resize(5);
    showVector(v1);
    v1.resize(10, 45);
    showVector(v1);
    v1.clear();
    showVector(v1);
}

结果：

 7、把vector当做普通数组使用：

 可以像使用动态数组一样使用vector。

举例：

void test08(void)
{
    vector<char> v1;
    v1.resize(40);
    strcpy(&v1[0], "hello World");
    printf("%s\n", &v1[0]);
}

输出hello World

8、异常处理：

 成员函数中仅at（）会抛出异常；