\/* MD \/ \u5bcc\u6587\u672c\u4e2d\u7684 .toc\uff08\u542b\u535a\u5ba2\u56ed\u642c\u5bb6\u7b49\u5d4c\u5957\u7ed3\u6784\uff09\uff1b.toc-box \u5728\u4fa7\u680f\uff0c\u4e0d\u53d7\u5f71\u54cd *\/
\n #content_views .toc,
\n \/* \u7f16\u8f91\u5668\u5e38\u5728\u76ee\u5f55\u524d\u540e\u63d2\u5165\u7a7a p\uff08:empty \u4ecd\u5360 20px\uff09\uff0c\u4e00\u5e76\u53bb\u6389\u907f\u514d\u9876\u7a7a\u9699 *\/
\n #content_views.markdown_views > p:empty:has(+ .toc),
\n #content_views.markdown_views > .toc + p:empty,
\n \/* \u5bcc\u6587\u672c\u65e7\u7248\u76ee\u5f55\u6807\u8bb0 *\/
\n #content_views.htmledit_views #main-toc,
\n #content_views.htmledit_views #hr-toc,
\n #content_views.htmledit_views p[id*=\\”-toc\\”] {
\n display: none !important;
\n }
\n \/* \u76ee\u5f55\u53bb\u6389\u540e\uff0c\u7d27\u8ddf\u7684\u9996\u4e2a\u6807\u9898\u4e0d\u518d\u591a\u51fa\u4e00\u5757\u4e0a\u8fb9\u8ddd *\/
\n #content_views.markdown_views > .toc + h1,
\n #content_views.markdown_views > .toc + h2,
\n #content_views.markdown_views > .toc + h3,
\n #content_views.markdown_views > .toc + h4,
\n #content_views.markdown_views > .toc + p:empty + h1,
\n #content_views.markdown_views > .toc + p:empty + h2,
\n #content_views.markdown_views > .toc + p:empty + h3,
\n #content_views.markdown_views > .toc + p:empty + h4 {
\n margin-top: 0 !important;
\n }<\/p>\n
\u8981\u5f04\u660e\u767d\u79fb\u52a8\u6784\u9020\u51fd\u6570\u662f\u4ec0\u4e48，\u9700\u8981\u9996\u5148\u4e86\u89e3\u4ec0\u4e48\u662f\u5de6\u503c\u53f3\u503c\u53ca\u53f3\u503c\u5f15\u7528，\u5982\u679c\u4e0d\u4e86\u89e3，\u53ef\u4ee5\u5148\u770b\u8fd9\u7bc7\u6587\u7ae0：c++\u5de6\u503c\u53f3\u503c\u548c\u53f3\u503c\u5f15\u7528<\/p>\n
\u79fb\u52a8\u6784\u9020\u51fd\u6570\u662fC++11\u5f15\u5165\u7684\u4e00\u79cd\u7279\u6b8a\u6784\u9020\u51fd\u6570，\u7528\u4e8e\u4ece\u4e34\u65f6\u5bf9\u8c61（\u53f3\u503c）"\u7a83\u53d6"\u8d44\u6e90\u6765\u521d\u59cb\u5316\u65b0\u5bf9\u8c61，\u800c\u4e0d\u662f\u8fdb\u884c\u6602\u8d35\u7684\u6df1\u62f7\u8d1d\u3002<\/p>\n
class MyString {
\n char* data;
\n size_t size;
\npublic:
\n \/\/ \u79fb\u52a8\u6784\u9020\u51fd\u6570：\u53c2\u6570\u662f\u53f3\u503c\u5f15\u7528 &&
\n MyString(MyString&& other) noexcept
\n : data(other.data), size(other.size) {
\n other.data = nullptr; \/\/ \u5173\u952e：\u628a\u6e90\u5bf9\u8c61\u7684\u8d44\u6e90\u7f6e\u7a7a
\n other.size = 0;
\n }
\n}; <\/p>\n
\u6838\u5fc3\u95ee\u9898：\u6df1\u62f7\u8d1d\u6602\u8d35<\/p>\n
\u8003\u8651 std::vector \u5185\u90e8\u6301\u6709\u4e00\u5757\u5806\u5185\u5b58：<\/p>\n
std::vector<int> v1 = {1,2,3,…,1000000};
\nstd::vector<int> v2 = std::move(v1); \/\/ \u671f\u671b：\u8f6c\u79fb\u6307\u9488，O(1) <\/p>\n
\u5982\u679c\u7528\u62f7\u8d1d\u6784\u9020：\u9700\u8981\u91cd\u65b0\u5206\u914d100\u4e07\u4e2aint\u5e76\u9010\u4e2a\u590d\u5236 \u2192 O(n)，\u6162\u3002<\/p>\n
\u5982\u679c\u7528\u79fb\u52a8\u6784\u9020：\u53ea\u9700\u628a\u5185\u90e8\u6307\u9488\u4ea4\u7ed9\u65b0\u5bf9\u8c61，\u628a\u6e90\u5bf9\u8c61\u6307\u9488\u7f6e\u7a7a \u2192 O(1)，\u5feb\u3002<\/p>\n
\u5178\u578b\u89e6\u53d1\u573a\u666f：<\/p>\n
\u51fd\u6570\u8fd4\u56de\u5c40\u90e8\u5bf9\u8c61（\u8fd4\u56de\u503c\u4f18\u5316\u914d\u5408）<\/p>\n<\/li>\n
\u5bb9\u5668\u6269\u5bb9\u65f6\u642c\u8fc1\u5143\u7d20（vector \u91cd\u65b0\u5206\u914d）<\/p>\n<\/li>\n
\u663e\u5f0f std::move \u8f6c\u79fb\u6240\u6709\u6743<\/p>\n<\/li>\n
\u4f20\u9012\u4e34\u65f6\u5bf9\u8c61<\/p>\n<\/li>\n<\/ul>\n
std::vector<std::string> getStrings() {
\n std::vector<std::string> v;
\n \/\/ … \u586b\u5145\u5927\u91cf\u5b57\u7b26\u4e32
\n return v; \/\/ \u79fb\u52a8\u800c\u975e\u62f7\u8d1d（RVO\/NRVO）
\n} <\/p>\n
\u719f\u6089c++\u7684\u8bdd，\u65e0\u8bba\u662f\u51fd\u6570\u4f20\u53c2\u8fd8\u662f\u8d4b\u503c\u7b49\u7b49，c++\u5f88\u5bb9\u6613\u5c06\u53d8\u91cf\u62f7\u8d1d\u4e00\u4e2a\u526f\u672c\u53bb\u64cd\u4f5c\u526f\u672c，\u4f46\u662f\u5982\u679c\u4f60\u5728\u7c7b\u4e2d\u58f0\u660e\u4e86\u79fb\u52a8\u6784\u9020\u51fd\u6570，\u7f16\u8bd1\u5668\u5c31\u4f1a\u5728\u6ee1\u8db3\u6761\u4ef6\u7684\u65f6\u5019\u5982\u8fd9\u91cc\u7684\u5178\u578b\u89e6\u53d1\u573a\u666f\u4e0d\u62f7\u8d1d\u800c\u662f\u79fb\u52a8，\u8fd9\u6837\u4ece\u6027\u80fd\u4e0a\u6765\u8bb2\u662f\u6709\u4f18\u5316\u7684<\/p>\n<\/p>\n
MyString.h<\/p>\n
#include <cstddef>
\n#include <cstring>
\n#include <iostream>
\n#include <utility>
\n#include <windows.h> \/\/ \u5fc5\u987b\u5305\u542b\u8fd9\u4e2a\u5934\u6587\u4ef6,\u4f7fvscode\u652f\u6301\u4e2d\u6587\u8f93\u51fa<\/p>\n
class MyString {
\npublic:
\n explicit MyString(const char* text = "") {
\n size = text == nullptr ? 0 : std::strlen(text);
\n data = new char[size + 1];
\n if (size == 0) {
\n data[0] = '\\\\0';
\n } else {
\n std::memcpy(data, text, size + 1);
\n }<\/p>\n
std::cout << "[\u6784\u9020] \u5185\u5bb9=\\\\"" << data
\n << "\\\\", \u8d44\u6e90\u5730\u5740=" << static_cast<const void*>(data) << '\\\\n';
\n }<\/p>\n
MyString(const MyString& other)
\n : data(new char[other.size + 1]), size(other.size) {
\n if (other.data == nullptr) {
\n data[0] = '\\\\0';
\n } else {
\n std::memcpy(data, other.data, size + 1);
\n }<\/p>\n
std::cout << "[\u62f7\u8d1d\u6784\u9020] \u6df1\u62f7\u8d1d\u5230\u8d44\u6e90\u5730\u5740="
\n << static_cast<const void*>(data) << '\\\\n';
\n }<\/p>\n
MyString(MyString&& other) noexcept
\n : data(other.data), size(other.size) {
\n other.data = nullptr;
\n other.size = 0;<\/p>\n
std::cout << "[\u79fb\u52a8\u6784\u9020] \u63a5\u7ba1\u8d44\u6e90\u5730\u5740="
\n << static_cast<const void*>(data)
\n << "，\u5e76\u5c06\u539f\u5bf9\u8c61\u7f6e\u4e3a\u7a7a\\\\n";
\n }<\/p>\n
MyString& operator=(const MyString& other) {
\n if (this == &other) {
\n return *this;
\n }<\/p>\n
char* newData = new char[other.size + 1];
\n if (other.data == nullptr) {
\n newData[0] = '\\\\0';
\n } else {
\n std::memcpy(newData, other.data, other.size + 1);
\n }<\/p>\n
delete[] data;
\n data = newData;
\n size = other.size;<\/p>\n
std::cout << "[\u62f7\u8d1d\u8d4b\u503c] \u91ca\u653e\u65e7\u8d44\u6e90\u5e76\u6df1\u62f7\u8d1d\u5230\u8d44\u6e90\u5730\u5740="
\n << static_cast<const void*>(data) << '\\\\n';
\n return *this;
\n }<\/p>\n
MyString& operator=(MyString&& other) noexcept {
\n if (this == &other) {
\n return *this;
\n }<\/p>\n
char* oldData = data;
\n data = other.data;
\n size = other.size;
\n other.data = nullptr;
\n other.size = 0;
\n delete[] oldData;<\/p>\n
std::cout << "[\u79fb\u52a8\u8d4b\u503c] \u91ca\u653e\u65e7\u8d44\u6e90\u5e76\u63a5\u7ba1\u8d44\u6e90\u5730\u5740="
\n << static_cast<const void*>(data)
\n << "，\u5e76\u5c06\u539f\u5bf9\u8c61\u7f6e\u4e3a\u7a7a\\\\n";
\n return *this;
\n }<\/p>\n
~MyString() {
\n if (data != nullptr) {
\n std::cout << "[\u6790\u6784] \u91ca\u653e\u8d44\u6e90\u5730\u5740="
\n << static_cast<const void*>(data)
\n << "，\u5185\u5bb9=\\\\"" << data << "\\\\"\\\\n";
\n } else {
\n std::cout << "[\u6790\u6784] \u7a7a\u5bf9\u8c61\u65e0\u9700\u91ca\u653e\u8d44\u6e90\\\\n";
\n }
\n delete[] data;
\n }<\/p>\n
const char* c_str() const {
\n return data == nullptr ? "" : data;
\n }<\/p>\n
std::size_t length() const {
\n return size;
\n }<\/p>\n
void print(const char* label) const {
\n std::cout << label << ": \u5185\u5bb9=\\\\"" << c_str()
\n << "\\\\", \u957f\u5ea6=" << size
\n << ", \u8d44\u6e90\u5730\u5740=" << static_cast<const void*>(data) << '\\\\n';
\n }<\/p>\n
private:
\n char* data;
\n std::size_t size;
\n}; <\/p>\n
TestMove.cpp<\/p>\n
#include "MyString.h"<\/p>\n
int main() {<\/p>\n
\/\/ \u8bbe\u7f6e\u63a7\u5236\u53f0\u8f93\u51fa\u7f16\u7801\u4e3a UTF-8
\n SetConsoleOutputCP(65001); <\/p>\n
MyString source("Hello, move semantics!");
\n source.print("source");<\/p>\n
std::cout << "\\\\n===== 1. \u79fb\u52a8\u6784\u9020：\u4ea4\u51fa\u8d44\u6e90\u6240\u6709\u6743 =====" << '\\\\n';
\n MyString moved(std::move(source));
\n source.print("source（\u79fb\u52a8\u540e）");
\n moved.print("moved");<\/p>\n
std::cout << "\\\\n===== 2. \u79fb\u52a8\u8d4b\u503c：\u63a5\u7ba1\u53e6\u4e00\u4e2a\u5bf9\u8c61\u7684\u8d44\u6e90 =====" << '\\\\n';
\n MyString target("old data");
\n target.print("target（\u79fb\u52a8\u524d）");
\n target = std::move(moved);
\n moved.print("moved（\u79fb\u52a8\u540e）");
\n target.print("target（\u79fb\u52a8\u540e）");<\/p>\n
std::cout << "\\\\n===== 3. \u88ab\u79fb\u52a8\u7684\u5bf9\u8c61\u53ef\u4ee5\u91cd\u65b0\u8d4b\u503c =====" << '\\\\n';
\n moved = MyString("reused");
\n moved.print("moved（\u91cd\u65b0\u8d4b\u503c\u540e）");<\/p>\n
std::cout << "\\\\n===== 4. main \u7ed3\u675f，\u5bf9\u8c61\u6309\u76f8\u53cd\u987a\u5e8f\u6790\u6784 =====" << '\\\\n';
\n return 0;
\n}<\/p>\n
\u53ef\u4ee5\u5c06\u4ee3\u7801\u62f7\u8d1d\u5230IDE\u8fd0\u884c\u4e00\u4e0b\u770b\u770b\u8fd0\u884c\u7ed3\u679c，\u8fd0\u884c\u7ed3\u679c\u6587\u5b57\u8f83\u591a\u5c31\u4e0d\u8d34\u51fa\u6765\u4e86\u4ee5\u514d\u5f71\u54cd\u4e0b\u9762\u7684\u9605\u8bfb<\/p>\n
| \u53c2\u6570\u7c7b\u578b<\/td>\n | T&&（\u53f3\u503c\u5f15\u7528），\u4e0d\u662f const T&&<\/td>\n<\/tr>\n |
| \u6807\u8bb0 noexcept<\/td>\n | std::vector \u6269\u5bb9\u65f6\u53ea\u6709\u5728\u79fb\u52a8\u6784\u9020\u4e3a noexcept \u65f6\u624d\u4f1a\u7528\u79fb\u52a8，\u5426\u5219\u9000\u5316\u4e3a\u62f7\u8d1d<\/td>\n<\/tr>\n |
| \u6e90\u5bf9\u8c61\u7f6e\u4e3a\u6709\u6548\u72b6\u6001<\/td>\n | \u5fc5\u987b\u8ba9 other \u5904\u4e8e\u53ef\u5b89\u5168\u6790\u6784\u7684\u72b6\u6001（\u901a\u5e38\u7f6e\u7a7a\u6307\u9488\/\u6e05\u7a7a）<\/td>\n<\/tr>\n |
| \u81ea\u8d4b\u503c\u68c0\u67e5<\/td>\n | \u79fb\u52a8\u8d4b\u503c\u4e2d\u8981\u68c0\u67e5 this != &other<\/td>\n<\/tr>\n |
| \u4e94\u6cd5\u5219<\/td>\n | \u5b9a\u4e49\u4e86\u6790\u6784\/\u62f7\u8d1d\/\u79fb\u52a8\u4e4b\u4e00，\u901a\u5e38\u9700\u8003\u8651\u5168\u90e8\u4e94\u4e2a<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u8fd9\u91cc\u63d0\u4e00\u4e0b\u5176\u4e2d\u7684\u4e24\u70b9<\/p>\n \u8ba9\u6211\u4eec\u56de\u5230\u4e0a\u8ff0\u4ee3\u7801\u4e2d\u7684\u5176\u4e2d\u4e00\u4e2a\u7247\u6bb5<\/p>\n MyString(MyString&& other) noexcept std::cout << "[\u79fb\u52a8\u6784\u9020] \u63a5\u7ba1\u8d44\u6e90\u5730\u5740=" other.data = nullptr; other.size = 0;<\/p>\n \u4e3a\u4ec0\u4e48\u8981\u628a\u539f\u5bf9\u8c61\u7f6e\u7a7a？\u56e0\u4e3a\u539f\u5bf9\u8c61\u662f\u4e2a\u53f3\u503c，\u9a6c\u4e0a\u5c31\u8981\u88ab\u9500\u6bc1\u4e86\u3002\u4f46\u5b83\u7684\u6790\u6784\u51fd\u6570\u8fd8\u662f\u4f1a\u8c03\u7528\u7684\u3002\u5982\u679c\u4e0d\u7f6e\u7a7a，\u6790\u6784\u51fd\u6570\u5c31\u4f1a\u628a data_ \u7ed9 delete \u6389\u2014\u2014\u90a3\u65b0\u5bf9\u8c61\u5c31\u6210\u91ce\u6307\u9488\u4e86\u3002<\/p>\n \u6790\u6784\u51fd\u6570\u8fd9\u4e48\u5199<\/p>\n ~MyString() { \u4ec0\u4e48\u662f\u4e94\u6cd5\u5219<\/p>\n Rule of Five（\u4e94\u6cd5\u5219，C++11 \u53ca\u4ee5\u540e） C++11 \u5f15\u5165\u4e86\u79fb\u52a8\u8bed\u4e49，\u65b0\u589e\u4e86\u4e24\u4e2a\u7279\u6b8a\u6210\u5458\u51fd\u6570\u3002\u4e94\u6cd5\u5219\u5efa\u8bae，\u5982\u679c\u4f60\u9700\u8981\u5b9a\u4e49（\u6216 =delete）\u4ee5\u4e0b\u4e94\u4e2a\u4e2d\u7684\u4efb\u610f\u4e00\u4e2a，\u5c31\u5e94\u8be5\u8003\u8651\u5168\u90e8\u4e94\u4e2a：<\/p>\n \u6790\u6784\u51fd\u6570<\/p>\n \u62f7\u8d1d\u6784\u9020\u51fd\u6570<\/p>\n \u62f7\u8d1d\u8d4b\u503c\u8fd0\u7b97\u7b26<\/p>\n \u79fb\u52a8\u6784\u9020\u51fd\u6570 (C++11)<\/p>\n \u79fb\u52a8\u8d4b\u503c\u8fd0\u7b97\u7b26 (C++11) \u8fd9\u4e5f\u662f\u4e3a\u4ec0\u4e48\u4e0a\u9762\u4ee3\u7801\u4e2d\u7684MyString \u5199\u4e86\u90a3\u4e48\u591a\u7684\u539f\u56e0，MyString.h\u5c31\u662f\u9075\u5faa\u4e86\u4e94\u6cd5\u5219<\/p>\n 3. \u7528 std::move \u5f3a\u5236\u8f6c\u79fb<\/h5>\nBuffer b1(1024); std::string s1 = "hello"; 4. \u5e38\u89c1\u9677\u9631<\/h5>\n\/\/ \u274c \u9519\u8bef：\u79fb\u52a8\u6784\u9020\u6ca1\u7f6e\u7a7a\u6e90\u5bf9\u8c61 \u2192 \u53cc\u91cd\u91ca\u653e \/\/ \u274c \u9519\u8bef：\u53c2\u6570\u5199\u6210 const T&& \u2192 \u65e0\u6cd5\u4fee\u6539\u6e90\u5bf9\u8c61 \/\/ \u274c \u9519\u8bef：\u79fb\u52a8\u6784\u9020\u672a\u6807 noexcept \u2192 vector \u6269\u5bb9\u8d70\u62f7\u8d1d \/\/ \u274c \u5bf9 const \u5bf9\u8c61 std::move \u65e0\u6548 \u2192 \u9000\u5316\u4e3a\u62f7\u8d1d 5. \u4f55\u65f6\u8be5\u5199\/\u4e0d\u8be5\u5199<\/h5>\n\u9700\u8981\u624b\u5199：\u7c7b\u81ea\u5df1\u7ba1\u7406\u8d44\u6e90（\u88f8\u6307\u9488\u3001\u6587\u4ef6\u53e5\u67c4\u3001socket \u7b49）<\/p>\n<\/li>\n \u4e0d\u9700\u8981\u624b\u5199：\u6210\u5458\u90fd\u662f std::string\/std::vector\/\u667a\u80fd\u6307\u9488\u7b49，\u7f16\u8bd1\u5668\u751f\u6210\u7684\u9ed8\u8ba4\u79fb\u52a8\u6784\u9020\u5df2\u8db3\u591f<\/p>\n<\/li>\n = default \u663e\u5f0f\u751f\u6210：<\/p>\n<\/li>\n<\/ul>\n class Widget { \/* MD \/ \u5bcc\u6587\u672c\u4e2d\u7684 .toc\uff08\u542b\u535a\u5ba2\u56ed\u642c\u5bb6\u7b49\u5d4c\u5957\u7ed3\u6784\uff09\uff1b.toc-box \u5728\u4fa7\u680f\uff0c\u4e0d\u53d7\u5f71\u54cd *\/#content_views .toc,\/* \u7f16\u8f91\u5668\u5e38\u5728\u76ee\u5f55\u524d\u540e\u63d2\u5165\u7a7a p\uff08:empty \u4ecd\u5360 20px\uff09\uff0c\u4e00\u5e76\u53bb\u6389\u907f\u514d\u9876\u7a7a\u9699 *\/#content_views.markdown_views > p:empty:has(+ .toc),#content_views.markdown_views > .toc + p:empty,\/* \u5bcc\u6587\u672c\u65e7\u7248\u76ee\u5f55\u6807\u8bb0 *\/#content<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[55,190],"topic":[],"class_list":["post-123273","post","type-post","status-publish","format-standard","hentry","category-server","tag-c","tag-190"],"yoast_head":"\n |