【STL】vector的insert方法详解
std::vector的四个insert重载函数：

void test_vector_insert(){ std::vector<int> v1;v1.push_back(10);v1.push_back(20);v1.push_back(30);std::cout << "v1 = " ;std::copy(v1.begin(), v1.end(), std::ostream_iterator<int>(std::cout, " "));std::cout << std::endl;// 方法1: v1.insert(v1.begin() + 1, 40);std::cout << "v1 = ";std::copy(v1.begin(), v1.end(), std::ostream_iterator<int>(std::cout, " "));std::cout << std::endl;// 方法3:v1.insert(v1.begin() + 2, 4, 50);std::cout << "v1 = ";std::copy(v1.begin(), v1.end(), std::ostream_iterator<int>(std::cout, " "));std::cout << std::endl;// 方法4:v1.insert(v1.begin() + 1, v1.begin() + 2, v1.begin() + 4);std::cout << "v1 = ";std::copy(v1.begin(), v1.end(), std::ostream_iterator<int>(std::cout, " "));std::cout << std::endl;}