vector :: capacity()函数以及C ++ STL中的示例
C++vector::capacity()函数
vector::capacity()是“vector”头文件的库函数，用于查找矢量的容量，它返回当前分配给该矢量的存储空间。
注意：要使用向量，请包含<vector>标头。
vector::capacity()函数的语法
vector::capacity();
参数：void–不接受任何参数。
返回值：size_type–返回容量，即向量的存储空间。
示例
Input:
vector<int> vector1{ 1, 2, 3, 4, 5 };
Function call:
cout << vector1.capacity();
Output:
8C++程序演示vector::capacity()函数的示例
//C++STL程序演示示例
//vector::capacity()函数
#include <iostream>
#include <vector>
using namespace std;
int main(){
vector<int> v1;
//printing the size & capacity of the vector
cout << "Total number of elements: " << v1.size() << endl;
cout << "Storage space: " << v1.capacity() << endl;
//推动元素
v1.push_back(10);
v1.push_back(20);
v1.push_back(30);
v1.push_back(40);
v1.push_back(50);
//printing the size & capacity of the vector
cout << "Total number of elements: " << v1.size() << endl;
cout << "Storage space: " << v1.capacity() << endl;
return 0;
}输出结果
Total number of elements: 0 Storage space: 0 Total number of elements: 5 Storage space: 8
参考：C++vector::capacity()