std::vector::size

size_type size() const noexcept;

Returns the number of elements in the vector.

返回vector中元素的个数。

This is the number of actual objects held in the vector, which is not necessarily equal to its storage capacity.

这个个数是vector中实际存放的元素个数，但不一定必须等于这个vector的容量。

Parameters

none

Return Value

The number of elements in the container.
返回值为元素个数。

Member type size_type is an unsigned integral type.

类型为无符号整数。

Example

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

// vector::size
#include <iostream>
#include <vector>

int main ()
{
  std::vector<int> myints;
  std::cout << "0. size: " << myints.size() << '\n';

  for (int i=0; i<10; i++) myints.push_back(i);
  std::cout << "1. size: " << myints.size() << '\n';

  myints.insert (myints.end(),10,100);
  std::cout << "2. size: " << myints.size() << '\n';

  myints.pop_back();
  std::cout << "3. size: " << myints.size() << '\n';

  return 0;
}

Output:

0. size: 0
1. size: 10
2. size: 20
3. size: 19

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
No contained elements are accessed: concurrently accessing or modifying them is safe.

容器将被访问。

容器内的元素不会被访问。同时访问或者修改他们都是安全的。

Exception safety

No-throw guarantee: this member function never throws exceptions.

该成员方法不会抛出异常。

//翻译的不好的地方请多多指导，可以在下面留言或者点击左上方邮件地址给我发邮件，指出我的错误以及不足，以便我修改，更好的分享给大家，谢谢。

转载请注明出处：http://blog.csdn.net/qq844352155

2014-8-12

于GDUT