C++ vector 容器

 //vector类  resemble array  自动扩容...  暂存于内存中
 //格式 vector<类（型）名> 对象名  example: vector<string> v; vector<int> i;
 //copy a entire file into a vector of string
 #include<fstream>
 #include<string>
 #include<iostream>
 #include<vector>
 using namespace std;
 int main()
 {
  vector<string> v;
  string  s;
  ofstream out("file.txt");
  for (int i = ; i < ; i++)
  {
   cout << "Please enter:" << endl;
   getline(cin, s);
   out << s << '\n';
  }
  out.close();
  ifstream in("file.txt");
  while (getline(in, s))//按行读取
   v.push_back(s);  //将string s压入vector v的尾部
  for (int i = ; i < v.size(); i++)
   cout <<i<<":"<< v[i] << endl;
  for (int i = ; i < v.size(); i++)
   v[i] += "!";//可以根据下标改变单元的值
  for (int i = ; i < v.size(); i++)
   cout << i << ":" << v[i] << endl;
  system("pause");
  return ;
 }