1 c[index] 返回索引index所指向的元素 2 c.at(index) 返回index所指向的元素(会进行边界检查) 3 c.front() 返回第一个元素(不会检查第一元素是否存在) 4 c.back() 返回最后一个元素(不会检查最后一个元素是否存在) 由于vector只提供了at函数的检查元素,所以对于越界或者访问空元素的情况,其结果是未定义...
插入元素:insert 1#include <iostream>2#include <vector>34voidPrint(conststd::vector<int>&v)5{6for(auto& e : v) std::cout << e <<"";7std::cout <<std::endl;8}910intmain()11{12std::vector<int>v;13v.emplace_back(1);14v.emplace_back(2);15v.emplace_back(3);16Print(v);1718...
函数原型：at(int index);返回索引index指向的数据 operator[];和普通数组取数据用法一致 front();返回...
{ String **strPtr = (String**)vector_at(vec, index); string_push_back(*strPtr, '\n'); string_concatenate(concat, *strPtr); } for (size_t index = 0; index < 5; index++) { string_deallocate(fruits[index]); } vector_deallocate(vec); clock_gettime(CLOCK_MONOTONIC, &end); ...
void push_back(const _Ty& _Val) { // insert by moving into element at end, provide strong guarantee emplace_back(_STD move(_Val)); } template <class... _Valty> decltype(auto) emplace_back(_Valty&&... _Val) { // insert by perfectly forwarding into element at end, provide strong...
int value = vec.at(2); // value will be 3Code language: C++ (cpp) Performance Considerations: at() is slightly slower than operator[] because of the boundary check. If an out-of-bounds index is provided, it throws an std::out_of_range exception. ...
* */ Array<T, A>& insertAt(index_t index, const T& value); /** * @~English * @brief Remove an element at the given index. * * @param index [in] The given index. * @return The reference of the array itself. * * @~Chinese * @brief 删除指定索引出的一个元素。 * *...
{ m_begin = begin; m_indices.insert(indices.begin(), indices.end()); } bool operator()(string & value) { const int index = distance(&m_begin[0], &value); set<size_t>::iterator target = m_indices.find(index); return target != m_indices.end(); } private: vector<string>::...
std::type_index 支持std::Vector么 std::type_index 本身并不直接支持std::vector或其他具体类型的容器,但它可以用来表示和比较任何类型的类型信息,包括std::vector。你可以使用std::type_index 来获取和比较std::vector的类型信息。获取std::vector的std::type_index 要获取一个std::vector的 s ...
inline CPixelEditUndoRedoAction(BYTE nPaletteIndex, DWORD dwOldColRef, DWORD dwNewColRef) { IMAGMANIPULATION im; SetPaletteManipulation(im, nPaletteIndex, dwOldColRef, dwNewColRef); _bSorted = false; if (!_bSorted) _aPixelActionsVec.push_back(im); else _aPixelActionsSet.insert(im); } ...