{"id":5300,"date":"2021-06-06T03:26:14","date_gmt":"2021-06-05T19:26:14","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=5300"},"modified":"2021-06-06T03:26:14","modified_gmt":"2021-06-05T19:26:14","slug":"c%e6%97%a5%e8%ae%b0-day52%ef%bc%9a%e5%b5%8c%e5%85%a5%e5%bc%8f%e6%8c%87%e9%92%88%e6%a6%82%e5%bf%b5%e3%80%81%e5%86%85%e5%ad%98%e6%b1%a0%e6%94%b9%e8%bf%9b%e7%89%88","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/5300","title":{"rendered":"C++\u65e5\u8bb0\u2014\u2014Day52\uff1a\u5d4c\u5165\u5f0f\u6307\u9488\u6982\u5ff5\u3001\u5185\u5b58\u6c60\u6539\u8fdb\u7248"},"content":{"rendered":"

\u539f\u6587\u5730\u5740<\/a><\/p>\n

 <\/p>\n

lucky0han 2020-04-08 23:45:53 380 \u6536\u85cf 1
\n\u5206\u7c7b\u4e13\u680f\uff1a C++\u65e5\u8bb0
\n\u7248\u6743
\n\u5d4c\u5165\u5f0f\u6307\u9488
\n\u4e00\u822c\u5e94\u7528\u5728\u5185\u5b58\u6c60\u76f8\u5173\u7684\u4ee3\u7801\u4e2d\uff0c\u6210\u529f\u4f7f\u7528\u5d4c\u5165\u5f0f\u6307\u9488\u6709\u4e2a\u524d\u63d0\u6761\u4ef6\uff1a\u7c7bA\u5bf9\u8c61\u7684sizeof\u5fc5\u987b\u4e0d\u5c0f\u4e8e4\u4e2a\u5b57\u8282<\/p>\n

\u5de5\u4f5c\u539f\u7406\uff1a\u501f\u7528A\u5bf9\u8c61\u6240\u5360\u7528\u7684\u5185\u5b58\u7a7a\u95f4\u4e2d\u7684\u524d4\u4e2a\u5b57\u8282\uff0c\u7528\u6765\u94fe\u4f4f\u8fd9\u4e9b\u7a7a\u95f2\u7684\u5185\u5b58\u5757\uff1b<\/p>\n

\u4f46\u662f\u4e00\u65e6\u67d0\u4e00\u5757\u5185\u5b58\u88ab\u5206\u914d\u51fa\u53bb\uff0c\u90a3\u4e48\u8fd9\u4e2a\u5757\u7684\u524d4\u4e2a\u5b57\u8282\u5c31\u4e0d\u5728\u9700\u8981\u4e86\uff0c\u6b64\u65f6\u8fd94\u4e2a\u5b57\u8282\uff08\u8fd9\u91cc\u76844\u5b57\u8282\u6307\u7684\u662f\u5f53\u524d\u7f16\u8bd1\u5668\u9ed8\u8ba4\u7684\u6307\u9488\u7c7b\u578b\u6240\u5360\u5185\u5b58\u5927\u5c0f\uff09\u53ef\u4ee5\u88ab\u7c7bA\u5bf9\u8c61\u6b63\u5e38\u4f7f\u7528\uff1b<\/p>\n

 <\/p>\n

 <\/p>\n

\u5d4c\u5165\u5f0f\u6307\u9488\u4ee3\u7801\u6f14\u793a
\nsizeof\u8d85\u8fc74\u5b57\u8282\u7684\u7c7b\u5c31\u53ef\u4ee5\u5b89\u5168\u7684\u4f7f\u7528\u5d4c\u5165\u5f0f\u6307\u9488<\/p>\n

namespace _nmsp3 {
\nclass A {
\npublic:
\nint m_i;
\n};
\nclass TestEP{
\npublic:
\nint m_i;
\nint m_j;<\/p>\n

public:
\nstruct obj { \/\/ \u7ed3\u6784
\nstruct obj *next; \/\/\u8fd9\u4e2anext\u5c31\u662f\u5d4c\u5165\u5f0f\u6307\u9488\uff0c\u81ea\u5df1\u662f\u4e00\u4e2aobj\u5bf9\u8c61\uff0c\u90a3\u4e48\u81ea\u5df1\u628a\u8fd9\u4e2a\u5bf9\u8c61\u7684next\u6307\u9488\u6307\u5411
\n\/\/\u53e6\u5916\u4e00\u4e2aobj\u7ed3\u6784\u5bf9\u8c61\uff0c\u6700\u7ec8\u591a\u4e2a\u81ea\u5df1\u8fd9\u79cd\u7c7b\u578b\u7684\u5bf9\u8c61\u901a\u8fc7\u94fe\u4e32\u8d77\u6765
\n};
\n};<\/p>\n

void func() {
\nTestEP mytest;
\ncout << sizeof(mytest) << endl;
\nTestEP::obj *ptemp;
\nptemp = reinterpret_cast<TestEP::obj *>(&mytest);
\nptemp->next = nullptr;
\n}
\n}<\/p>\n

int main()
\n{
\n_nmsp3::func();
\nreturn 0;
\n}
\n\u8fd9\u91cc\u7684\u6d41\u7a0b\u7684\u610f\u601d\u662f\uff1a\u5c06\u751f\u6210\u7684 mytest \u5bf9\u8c61\u901a\u8fc7\u6307\u9488\u8f6c\u6362\u53d8\u6210 obj\u7684\u5730\u5740\u7c7b\u578b\uff0c \u540c\u65f6\u751f\u6210\u4e00\u4e2a\u65b0\u7684obj\u6307\u9488\u7528\u6765\u5b58\u653e\u5b83\uff0c\u8f6c\u6362\u7c7b\u578b\u4ee5\u540emytest\u5bf9\u8c61\u7684\u524d\u534a\u90e8\u5206\u5219\u4e3aobj\u5bf9\u8c61\uff0c\u6b64\u65f6\u5219\u53ef\u4ee5\u8c03\u7528\u5b83\u7684next \u5bf9\u8c61\u6307\u5411\u5176\u4ed6\u7684 obj\u7c7b\u578b\u5730\u5740\u3002<\/p>\n

 <\/p>\n

\u5d4c\u5165\u5f0f\u5185\u5b58\u6c60\u6539\u8fdb
\nnamespace _nmsp4 {
\nclass myallocator {
\npublic:
\nvoid *allocate(size_t size) {
\nobj *tmplink;
\nif (m_FreePosi == nullptr) {
\nsize_t realsize = m_sTrunkCout * size; \/\/\u7533\u8bf7m_TrunkCout\u500d\u5185\u5b58
\nm_FreePosi = reinterpret_cast<obj *>(malloc(realsize)); \/\/\u8fd9\u91cc\u7684new\u662f\u7cfb\u7edf\u7684new
\ntmplink = m_FreePosi;
\n\/\/\u628a\u5206\u914d\u51fa\u6765\u7684\u8fd9\u5757\u5185\u5b58\uff0c\u5f7c\u6b64\u8981\u8fde\u8d77\u6765\uff0c\u4f9b\u540e\u7eed\u4f7f\u7528
\nfor (int i = 0; i< m_sTrunkCout – 1; ++i) {
\ntmplink->next = reinterpret_cast<obj *>(reinterpret_cast<char *>(tmplink) + size);
\ntmplink = tmplink->next;
\n}
\ntmplink->next = nullptr;
\n}
\ntmplink = m_FreePosi;
\nm_FreePosi = m_FreePosi->next;
\nreturn tmplink;
\n}<\/p>\n

void deallocate(void *phead) {
\nreinterpret_cast<obj *>(phead)->next = m_FreePosi;
\nm_FreePosi = reinterpret_cast<obj *>(phead);
\n}<\/p>\n

private:
\nstruct obj {
\nstruct obj *next;
\n};
\nobj* m_FreePosi;
\nint m_sTrunkCout = 5;\/\/\u4e00\u6b21\u5206\u914d\u591a\u5c11\u8be5\u7c7b\u5185\u5b58
\n};<\/p>\n

class A {
\npublic:
\nint m_i;
\nint m_j;
\nstatic myallocator myalloc;
\nstatic void *operator new(size_t size) {
\nreturn myalloc.allocate(size);
\n}<\/p>\n

static void operator delete(void *phead) {
\nmyalloc.deallocate(phead);
\n}
\n};<\/p>\n

myallocator A::myalloc;<\/p>\n

void func() {
\nA *mypa[100];
\nfor (int i = 0; i < 15; ++i) {
\nmypa[i] = new A();
\nprintf(“%p\\n”, mypa[i]);
\n}
\n}
\n}<\/p>\n

int main()
\n{
\n_nmsp4::func();
\nreturn 0;
\n}
\n\u63d0\u793a\uff1a\u5e73\u65f6\u7528 ++i \u800c\u4e0d\u662f i++\u53ef\u4ee5\u5c11\u751f\u6210\u4e00\u6b21\u4e34\u65f6\u5bf9\u8c61\u3002<\/p>\n

\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014
\n\u7248\u6743\u58f0\u660e\uff1a\u672c\u6587\u4e3aCSDN\u535a\u4e3b\u300clucky0han\u300d\u7684\u539f\u521b\u6587\u7ae0\uff0c\u9075\u5faaCC 4.0 BY-SA\u7248\u6743\u534f\u8bae\uff0c\u8f6c\u8f7d\u8bf7\u9644\u4e0a\u539f\u6587\u51fa\u5904\u94fe\u63a5\u53ca\u672c\u58f0\u660e\u3002
\n\u539f\u6587\u94fe\u63a5\uff1ahttps:\/\/blog.csdn.net\/weixin_38278993\/article\/details\/105390425<\/p>\n","protected":false},"excerpt":{"rendered":"

\u539f\u6587\u5730\u5740   lucky0ha<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[119],"class_list":["post-5300","post","type-post","status-publish","format-standard","hentry","tag-03-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/5300","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=5300"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/5300\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=5300"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=5300"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=5300"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}