void vecInOutPut(std::vector<int>& vec_test)
{
if (vec_test.size() > 2)
{
//下标
cout << vec_test[0] << endl;
cout << vec_test[vec_test.size()-1] << endl;
//at
cout << vec_test.at(0) << endl;
cout << vec_test.at(vec_test.size()-1) << endl;
//front,back函数
cout << vec_test.front() << endl;
cout << vec_test.back() << endl;
//指针
std::vector<int>::iterator Begin = vec_test.begin();
std::vector<int>::iterator end = vec_test.end()-1;
cout << *Begin << endl;
cout << *end << endl;
}
}