Library type vector

Library type vectorrepresents a collection of objects, where all objects are the same type.

Because vectorthe houses other objects, it is often referred to as a container.

To use the vectorneed to include the header file <vector>.

vectorIt is not a template type, a vectortype produced must contain vectorthe type of elements, for example: vector<int>.

Definition and initialization vector objects

• List initialize vectorobjects

vector<string> articles = {"a","an","the"};

• Create a specified number of elements

vector<int> ivec(10,-1);

• Initialization value

vector<int> ivec(10);   //10个元素，每个都初始化为0
vector<string> svec(10);    //10个元素，每个都是空string对象

• A list of the initial value or the number of elements

vector<int> v1(10);     //v1有10个元素，每个值都是0
vector<int> v2{ 10 };   //v2有1个元素，其值为10
vector<int> v3(10, 1);      //v3有10个元素，每个值都是1
vector<int> v4{ 10, 1 };    //v4有2个元素，值分别是10和1

vector<string> v5{ "hi" };  //列表初始化，v5有一个元素
vector<string> v6("hi");    //错误，不能使用字符串字面值构建vector对象
vector<string> v7(10);  //v7有10个默认初始化的元素
vector<string> v8{ 10, "hi"};   //v8有10个值为"hi"的元素

vector Compatible Operating

Not in the form of the additive elements with subscript

vector<int> ivec;
for(decltype(ivec.size())ix = 0;ix!=10;++ix)
    ivec[ix] = ix;  //严重错误，ivec不包含任何元素

vectorObjects and stringobject subscript operator may be used to access an element already present, but not in an additive element. '