vector - capacity(容量)

// 2018/04/15 19:12:27
// vector - capacity(容量)/*Size指目前容器中实际有多少元素，对应的resize(size_type)会在容器尾添加或删除一些元素，来调整容器中实际的内容，使容器达到指定的大小。Capacity指最少要多少元素才会使其容量重新分配，对应reserve(size_type new_size)会这置这个capacity值，使它不小于所指定的new_size。故用reserve(size_type)只是扩大capacity值，这些内存空间可能还是“野”的，如果此时使用"[ ]"来 访问，则可能会越界。而resize(size_type new_size)会真正使容器具有new_size个对象。 */
#include <iostream>
#include <vector>using namespace std;int main(){vector<int> v(10);cout << "Size of v = " << v.size() << endl;cout << "Capacity of v =" << v.capacity() << endl;v.resize(100);cout << "After resizing:" << endl;cout << "Size of v = " << v.size() << endl;cout << "Capacity of v = " << v.capacity() << endl;return 0;
}
/* OUTPUT:Size of v = 10Capacity of v =10After resizing:Size of v = 100Capacity of v = 100 */