vector

is a collection of objects. is often referred to as a container because it “contains” other objects.

🤝template不是class，更像是一个操作让编译器做，从而去产生一个class，他需要额外的信息，而额外的信息用尖括号包围。

Define and Initialize

vector<int> ivec;         // default to empty
vector<int> ivec2(ivec);  // copy
vector<int> ivec3 = ivec; // copy
vector<int> ivec4(10, 1); // 10 elements with each 1
vector<int> ivec5(10);    // 10 elements with each 0
 
vector<string> art = {“a”, “ab”}; // list init
vector<string> art2{“a”, “ab”};   // list init
vector<string> art3(“a”, “ab”);   // error
vector<string> art5{10, “hi”};    // construct

这么多个例子只是为了对照，不为了记忆。

Using an Array to Initialize a vector

int arr[] = {0, 1, 2, 3}
vector<int> ivec(arr+1, arr+2);

construct with begin and end pointer arguments.（左开右闭）

Operators

operators	effect
[]	subscript
=	assign, copy to; the r-h operand can be either object or curly brace
==, !=	if is equal in every detail
<, ⇐, >, >=	Have their normal meanings using dictionary ordering.

Functions

member funcs	effect
unknown push_back(value)	add a element at the end
bool empty()	true if is empty
vector<type>::size_type size()	number of elements
iterator funcs	🔗 Iterators