Vector声明限定元素数目的话，添加元素的个数就不能超过这个值吗？
#include <iostream>#include <vector>#include <string>using namespace std;class Point{public: int id; char *context; double scroe; Point(int i,char *j,double d) { id = i; context = j; scroe = d; };//要不要这个分号，貌似都可以。 Point(){};};vector<Point> cities;//没有指定cities有几个元素。这样程序没有问题、//vector<Point> cities(1);这样声明：vector<Point> cities[2]，程序编译通过，运行时崩溃，怎么回事啊。void add_points(Point sentinel){ cities.push_back(sentinel);}void main(void){ Point mypoint0(0,"test0",0.1); add_points(mypoint0);//调用push_back()一次就可以增加一个vector元素。 Point mypoint1(1,"test1",0.2); add_points(mypoint1); Point mypoint2(2,"test2",0.3); add_points(mypoint2); cout<<"the length of vector is "<<cities.size()<<endl;//调用size()求vector的长度 for (unsigned int i=0;i<cities.size();i++) { cout<<"id: "<<cities[i].id<<" context: "<<cities[i].context<<" scroe: "<<cities[i].scroe<<endl; //vector可以用下标操作符[i]来操作。跟数组类似。 } }