C++ 访问vector数组头尾的四种方法

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;
	}
}