std::copy对std::vector、std::set、数组的使用
注意:std::copy只负责复制,不负责申请空间,所以复制前必须有足够的空间!!!
std::copy的函数形式为:
std::copy(src_start_iter, src_end_iter, std::back_inserter(dst_container));
以下为写的测试代码:
#include <iostream> #include <string> #include <algorithm> #include <vector> #include <set> #include <map> void stdCopyTest() { // vector copy to vector { std::vector<int> vtSrc = { 1, 2, 3, 4, 5 }; std::vector<int> vtDst(6, 0); // std::vector(size, init_data), insert into begin,it must be new enough space first. std::copy(vtSrc.begin(), vtSrc.end(), vtDst.begin()); for (size_t i = 0, uSize = vtDst.size(); i < uSize; ++i) { std::cout << vtDst[i] << ; } std::cout << std::endl; std::vector<int> vtDst01(0); std::copy(vtSrc.begin(), vtSrc.end(), std::back_inserter(vtDst01)); for (size_t i = 0, uSize = vtDst01.size(); i < uSize; ++i) { std::cout << vtDst01[i] << ; } std::cout << std::endl; } // set insert into vector { std::set<int> setSrc = { 5, 4, 3, 2, 1 }; std::vector<int> vtDst; std::copy(setSrc.begin(), setSrc.end(), std::back_inserter(vtDst)); for (size_t i = 0, uSize = vtDst.size(); i < uSize; ++i) { std::cout << vtDst[i] << ; } std::cout << std::endl; } // array insert into vector { int szSrc[5] = { 1, 2, 3, 4, 5 }; std::vector<int> vtDst; std::copy(szSrc, szSrc + sizeof(szSrc) / sizeof(int), std::back_inserter(vtDst)); for (size_t i = 0, uSize = vtDst.size(); i < uSize; ++i) { std::cout << vtDst[i] << ; } std::cout << std::endl; } // vector insert into array { std::vector<int> vtSrc = { 1, 2, 3, 4, 5 }; int szDst[8] = { -1 }; std::copy(vtSrc.begin(), vtSrc.end(), szDst); for (size_t i = 0, uSize = vtSrc.size(); i < uSize; ++i) { std::cout << szDst[i] << ; } std::cout << std::endl; } // array insert into array { int szSrc[5] = { 1, 2, 3, 4, 5 }; int szDst[8] = { -1 }; std::copy(szSrc, szSrc + sizeof(szSrc) / sizeof(int), szDst); for (size_t i = 0, uSize = sizeof(szSrc) / sizeof(int); i < uSize; ++i) { std::cout << szDst[i] << ; } std::cout << std::endl; } // map copy to map { std::map<int, std::string> mp4Src = { std::pair<int, std::string>(1, "abc123"), std::pair<int, std::string>(2, "bcd456"), std::pair<int, std::string>(3, "cde789"), }; std::cout << "***********************" << std::endl; std::map<int, std::string> mp4Dst; mp4Dst.insert(mp4Src.begin(), mp4Src.end()); for (auto iter = mp4Dst.begin(); iter != mp4Dst.end(); ++iter) { std::cout << iter->first << ": " << iter->second << std::endl; } std::cout << "***********************" << std::endl; } return; }