C++编程语言中有一种叫做Vector的应用方法,它的作用在实际编程中是非常重要的。在这里我们将会为大家详细介绍一下C++ Vector的相关应用技巧及基本内容,希望能给大家带来一些帮助。
(1)vector< 类型 > 标识符 ;
(2)vector< 类型 > 标识符(最大容量) ;
(3)vector< 类型 > 标识符(最大容量,初始所有值);
(4) int i[4] = {12,3,4,5};
vector< 类型 > vi(i , i+2); //得到i索引值为3以后的值 ;
(5)vector< vector<int> > //vi 定义2维的容器;记得一定要有空格,不然会报错
vector< int > line
// 在使用的时候一定要首先将vi个行进行初始化;
for(int i = 0 ; i < 10 ; i ++)
{
line.push_back(i);
}
/// 个人认为使用vector定义二维数组很好,
因为是长度可以不预先确定。很好。
(6)C++ Vector排序
vector< int > vi ; vi.push_back(1); vi.push_back(3); vi.push_back(0); sort(vi.begin() , vi.end()); //小到大 reverse(vi.begin(),vi.end()) //从大道小
(7)顺序访问
vector < int > vi ; for( int i = 0 ; i < 10 ; i ++) { vi.push_back(i); } for(int i = 0 ; i < 10 ; i ++) /// 第一种调用方法 { cout <<vi[i] <<" " ; } for(vector<int>::iterator it = vi.begin() ; it !=vi.end() ; it++) //第二种调用方法 { cout << *it << " " ; }
(8)寻找
vector < int > vi ; for( int i = 0 ; i < 10 ; i ++) { vi.push_back(i); } vector < int >::interator it = find(vi.begin() , vi.end,3) ; cout << *it << endl ; //返回容器内找到值的位置。
(9)使用数组对C++ Vector进行初始化
int i[10] ={1,2,3,4,5,6,7,78,8} ; //第一种 vector<int> vi(i+1,i+3); ///从第2个元素到第三个元素 for(vector <int>::interator it = vi.begin() ; it != vi.end() ; it++) { cout << *it <<" " ; }
(10) 结构体类型
struct temp
{
public :
string str ;
public :
int id ;
}tmp;
int main()
{
vector <temp> t ;
temp w1 ;
w1.str = "Hellowor" ;
w1.id = 1 ;
t.push_back(t1);
cout << w1.str << "," <<w1.id <<endl ;
return 0 ;
}
C++ Vector的基本介绍就为大家介绍到这里。
vector::push_back
public member function
void push_back ( const T& x );
Add element at the end
Adds a new element at the end of the vector, after its current last element. The content of this new element is initialized to a copy of x.
This effectively increases the vector size by one, which causes a reallocation of the internal allocated storage if the vector size was equal to the vector capacity before the call. Reallocations invalidate all previously obtained iterators, references and pointers.
Parameters
x
Value to be copied to the new element.
T is the first template parameter (the type of the elements stored in the vector).
Return value
none
If a reallocation happens, it is performed using Allocator::allocate(), which may throw exceptions (for the default allocator, bad_alloc is thrown if the allocation request does not succeed).
Example
// vector::push_back#include <iostream>#include <vector>intmain () { std::vector<int> myvector;intmyint; std::cout <<"Please enter some integers (enter 0 to end):\n";do{ std::cin >> myint; myvector.push_back (myint); }while(myint); std::cout <<"myvector stores " <<int(myvector.size()) <<" numbers.\n";return0; }
The example uses push_back to add a new element to the vector each time a new integer is read.
Complexity
Constant (amortized time, reallocation may happen).
See also
vector::pop_back | Delete last element (public member function) |
vector::insert | Insert elements (public member function) |