{"id":4391,"date":"2020-07-21T17:05:25","date_gmt":"2020-07-21T09:05:25","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=4391"},"modified":"2020-07-21T17:05:25","modified_gmt":"2020-07-21T09:05:25","slug":"operator%e5%92%8coperatorint%e7%9a%84%e5%8c%ba%e5%88%ab","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/4391","title":{"rendered":"operator++()\u548coperator++(int)\u7684\u533a\u522b"},"content":{"rendered":"

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

 <\/p>\n

\n

\u5f88\u4e45\u4ee5\u524d\uff08\u516b\u5341\u5e74\u4ee3\uff09\uff0c\u6ca1\u6709\u529e\u6cd5\u533a\u5206++\u548c–\u64cd\u4f5c\u7b26\u7684\u524d\u7f00\u4e0e\u540e\u7f00\u8c03\u7528\u3002\u8fd9\u4e2a\u95ee\u9898\u906d\u5230\u7a0b\u5e8f\u5458\u7684\u62a5\u6028\uff0c\u4e8e\u662fC++\u8bed\u8a00\u5f97\u5230\u4e86\u6269\u5c55\uff0c\u5141\u8bb8\u91cd\u8f7dincrement \u548c decrement\u64cd\u4f5c\u7b26\u7684\u4e24\u79cd\u5f62\u5f0f\u3002<\/p>\n

\u7136\u800c\u6709\u4e00\u4e2a\u53e5\u6cd5\u4e0a\u7684\u95ee\u9898\uff0c\u91cd\u8f7d\u51fd\u6570\u95f4\u7684\u533a\u522b\u51b3\u5b9a\u4e8e\u5b83\u4eec\u7684\u53c2\u6570\u7c7b\u578b\u4e0a\u7684\u5dee\u5f02\uff0c\u4f46\u662f\u4e0d\u8bba\u662fincrement\u6216decrement\u7684\u524d\u7f00\u8fd8\u662f\u540e\u7f00\u90fd\u53ea\u6709\u4e00\u4e2a\u53c2\u6570\u3002\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u8bed\u8a00\u95ee\u9898\uff0cC++\u89c4\u5b9a\u540e\u7f00\u5f62\u5f0f\u6709\u4e00\u4e2aint\u7c7b\u578b\u53c2\u6570\uff0c\u5f53\u51fd\u6570\u88ab\u8c03\u7528\u65f6\uff0c\u7f16\u8bd1\u5668\u4f20\u9012\u4e00\u4e2a0\u505a\u4e3aint\u53c2\u6570\u7684\u503c\u7ed9\u8be5\u51fd\u6570\uff1a<\/p>\n\n\n\n
class UPInt { \/\/ “unlimited precision int”
\npublic:
\nUPInt& operator++(); \/\/ ++ \u524d\u7f00
\nconst UPInt operator++(int); \/\/ ++ \u540e\u7f00
\nUPInt& operator–(); \/\/ — \u524d\u7f00
\nconst UPInt operator–(int); \/\/ — \u540e\u7f00
\nUPInt& operator+=(int); \/\/ += \u64cd\u4f5c\u7b26\uff0cUPInts
\n\/\/ \u4e0eints \u76f8\u8fd0\u7b97
\n…
\n};<\/p>\n

UPInt i;<\/p>\n

++i; \/\/ \u8c03\u7528 i.operator++();
\ni++; \/\/ \u8c03\u7528 i.operator++(0);
\n–i; \/\/ \u8c03\u7528 i.operator–();
\ni–; \/\/ \u8c03\u7528 i.operator–(0);<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u8fd9\u4e2a\u89c4\u8303\u6709\u4e00\u4e9b\u53e4\u602a\uff0c\u4e0d\u8fc7\u4f60\u4f1a\u4e60\u60ef\u7684\u3002\u800c\u5c24\u5176\u8981\u6ce8\u610f\u7684\u662f\u8fd9\u4e9b\u64cd\u4f5c\u7b26\u524d\u7f00\u4e0e\u540e\u7f00\u5f62\u5f0f\u8fd4\u56de\u503c\u7c7b\u578b\u662f\u4e0d\u540c\u7684\u3002\u524d\u7f00\u5f62\u5f0f\u8fd4\u56de\u4e00\u4e2a\u5f15\u7528\uff0c\u540e\u7f00\u5f62\u5f0f\u8fd4\u56de\u4e00\u4e2aconst\u7c7b\u578b\u3002\u4e0b\u9762\u6211\u4eec\u5c06\u8ba8\u8bba++\u64cd\u4f5c\u7b26\u7684\u524d\u7f00\u4e0e\u540e\u7f00\u5f62\u5f0f\uff0c\u8fd9\u4e9b\u8bf4\u660e\u4e5f\u540c\u6837\u4f7f\u7528\u4e0e–\u64cd\u4f5c\u7b26\u3002<\/p>\n

\u4ece\u4f60\u5f00\u59cb\u505aC\u7a0b\u5e8f\u5458\u90a3\u5929\u5f00\u59cb\uff0c\u4f60\u5c31\u8bb0\u4f4fincrement\u7684\u524d\u7f00\u5f62\u5f0f\u6709\u65f6\u53eb\u505a\u201c\u589e\u52a0\u7136\u540e\u53d6\u56de\u201d\uff0c\u540e\u7f00\u5f62\u5f0f\u53eb\u505a\u201c\u53d6\u56de\u7136\u540e\u589e\u52a0\u201d\u3002\u8fd9\u4e24\u53e5\u8bdd\u975e\u5e38\u91cd\u8981\uff0c\u56e0\u4e3a\u5b83\u4eec\u662fincrement\u524d\u7f00\u4e0e\u540e\u7f00\u7684\u5f62\u5f0f\u4e0a\u7684\u89c4\u8303\u3002<\/p>\n\n\n\n
\/\/ \u524d\u7f00\u5f62\u5f0f\uff1a\u589e\u52a0\u7136\u540e\u53d6\u56de\u503c<\/p>\n

UPInt& UPInt::operator++()
\n{
\n*this += 1; \/\/ \u589e\u52a0
\nreturn *this; \/\/ \u53d6\u56de\u503c
\n}<\/p>\n

\/\/ postfix form: fetch and increment<\/p>\n

const UPInt UPInt::operator++(int)
\n{
\nUPInt oldValue = *this; \/\/ \u53d6\u56de\u503c
\n++(*this); \/\/ \u589e\u52a0
\nreturn oldValue; \/\/ \u8fd4\u56de\u88ab\u53d6\u56de\u7684\u503c
\n}<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u540e\u7f00\u64cd\u4f5c\u7b26\u51fd\u6570\u6ca1\u6709\u4f7f\u7528\u5b83\u7684\u53c2\u6570\u3002\u5b83\u7684\u53c2\u6570\u53ea\u662f\u7528\u6765\u533a\u5206\u524d\u7f00\u4e0e\u540e\u7f00\u51fd\u6570\u8c03\u7528\u3002\u5982\u679c\u4f60\u6ca1\u6709\u5728\u51fd\u6570\u91cc\u4f7f\u7528\u53c2\u6570\uff0c\u8bb8\u591a\u7f16\u8bd1\u5668\u4f1a\u663e\u793a\u8b66\u544a\u4fe1\u606f\uff0c\u5f88\u4ee4\u4eba\u8ba8\u538c\u3002\u4e3a\u4e86\u907f\u514d\u8fd9\u4e9b\u8b66\u544a\u4fe1\u606f\uff0c\u4e00\u79cd\u7ecf\u5e38\u4f7f\u7528\u7684\u65b9\u6cd5\u65f6\u7701\u7565\u6389\u4f60\u4e0d\u60f3\u4f7f\u7528\u7684\u53c2\u6570\u540d\u79f0\uff1b\u5982\u4e0a\u6240\u793a\u3002<\/p>\n

\u5f88\u660e\u663e\u4e00\u4e2a\u540e\u7f00increment\u5fc5\u987b\u8fd4\u56de\u4e00\u4e2a\u5bf9\u8c61\uff08\u5b83\u8fd4\u56de\u7684\u662f\u589e\u52a0\u524d\u7684\u503c\uff09\uff0c\u4f46\u662f\u4e3a\u4ec0\u4e48\u662fconst\u5bf9\u8c61\u5462\uff1f\u5047\u8bbe\u4e0d\u662fconst\u5bf9\u8c61\uff0c\u4e0b\u9762\u7684\u4ee3\u7801\u5c31\u662f\u6b63\u786e\u7684\uff1a<\/p>\n\n\n\n
UPInt i;
\ni++++; \/\/ \u4e24\u6b21increment\u540e\u7f00
\n\/\/ \u8fd0\u7b97<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u8fd9\u7ec4\u4ee3\u7801\u4e0e\u4e0b\u9762\u7684\u4ee3\u7801\u76f8\u540c\uff1a<\/p>\n\n\n\n
i.operator++(0).operator++(0);<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5f88\u660e\u663e\uff0c\u7b2c\u4e00\u4e2a\u8c03\u7528\u7684operator++\u51fd\u6570\u8fd4\u56de\u7684\u5bf9\u8c61\u8c03\u7528\u4e86\u7b2c\u4e8c\u4e2aoperator++\u51fd\u6570\u3002<\/p>\n

\u6709\u4e24\u4e2a\u7406\u7531\u5bfc\u81f4\u6211\u4eec\u5e94\u8be5\u538c\u6076\u4e0a\u8ff0\u8fd9\u79cd\u505a\u6cd5\uff0c\u7b2c\u4e00\u662f\u4e0e\u5185\u7f6e\u7c7b\u578b\u884c\u4e3a\u4e0d\u4e00\u81f4\u3002\u5f53\u8bbe\u8ba1\u4e00\u4e2a\u7c7b\u9047\u5230\u95ee\u9898\u65f6\uff0c\u4e00\u4e2a\u597d\u7684\u51c6\u5219\u662f\u4f7f\u8be5\u7c7b\u7684\u884c\u4e3a\u4e0eint\u7c7b\u578b\u4e00\u81f4\u3002\u800cint\u7c7b\u578b\u4e0d\u5141\u8bb8\u8fde\u7eed\u8fdb\u884c\u4e24\u6b21\u540e\u7f00increment\uff1a<\/p>\n\n\n\n
int i;
\ni++++; \/\/ \u9519\u8bef!<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u7b2c\u4e8c\u4e2a\u539f\u56e0\u662f\u4f7f\u7528\u4e24\u6b21\u540e\u7f00increment\u6240\u4ea7\u751f\u7684\u7ed3\u679c\u4e0e\u8c03\u7528\u8005\u671f\u671b\u7684\u4e0d\u4e00\u81f4\u3002\u5982\u4e0a\u6240\u793a\uff0c\u7b2c\u4e8c\u6b21\u8c03\u7528operator++\u6539\u53d8\u7684\u503c\u662f\u7b2c\u4e00\u6b21\u8c03\u7528\u8fd4\u56de\u5bf9\u8c61\u7684\u503c\uff0c\u800c\u4e0d\u662f\u539f\u59cb\u5bf9\u8c61\u7684\u503c\u3002\u56e0\u6b64\u5982\u679c\uff1a<\/p>\n\n\n\n
i++++;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u662f\u5408\u6cd5\u7684\uff0ci\u5c06\u4ec5\u4ec5\u589e\u52a0\u4e86\u4e00\u6b21\u3002\u8fd9\u4e0e\u4eba\u7684\u76f4\u89c9\u76f8\u8fdd\u80cc\uff0c\u4f7f\u4eba\u8ff7\u60d1\uff08\u5bf9\u4e8eint\u7c7b\u578b\u548cUPInt\u90fd\u662f\u4e00\u6837\uff09,\u6240\u4ee5\u6700\u597d\u7981\u6b62\u8fd9\u4e48\u505a\u3002<\/p>\n

C++\u7981\u6b62int\u7c7b\u578b\u8fd9\u4e48\u505a\uff0c\u540c\u65f6\u4f60\u4e5f\u5fc5\u987b\u7981\u6b62\u4f60\u81ea\u5df1\u5199\u7684\u7c7b\u6709\u8fd9\u6837\u7684\u884c\u4e3a\u3002\u6700\u5bb9\u6613\u7684\u65b9\u6cd5\u662f\u8ba9\u540e\u7f00increment \u8fd4\u56deconst\u5bf9\u8c61\u3002\u5f53\u7f16\u8bd1\u5668\u9047\u5230\u8fd9\u6837\u7684\u4ee3\u7801\uff1a<\/p>\n\n\n\n
i++++; \/\/ same as i.operator++(0).operator++(0);<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u5b83\u53d1\u73b0\u4ece\u7b2c\u4e00\u4e2aoperator++\u51fd\u6570\u8fd4\u56de\u7684const\u5bf9\u8c61\u53c8\u8c03\u7528operator++\u51fd\u6570\uff0c\u7136\u800c\u8fd9\u4e2a\u51fd\u6570\u662f\u4e00\u4e2anon\uff0dconst\u6210\u5458\u51fd\u6570\uff0c\u6240\u4ee5const\u5bf9\u8c61\u4e0d\u80fd\u8c03\u7528\u8fd9\u4e2a\u51fd\u6570\u3002\u5982\u679c\u4f60\u539f\u6765\u60f3\u8fc7\u8ba9\u4e00\u4e2a\u51fd\u6570\u8fd4\u56deconst\u5bf9\u8c61\u6ca1\u6709\u4efb\u4f55\u610f\u4e49\uff0c\u73b0\u5728\u4f60\u5c31\u77e5\u9053\u6709\u65f6\u8fd8\u662f\u6709\u7528\u7684\uff0c\u540e\u7f00increment\u548cdecrement\u5c31\u662f\u4f8b\u5b50\u3002\uff08\u66f4\u591a\u7684\u4f8b\u5b50\u53c2\u89c1Effective C++ \u6761\u6b3e21\uff09<\/p>\n

\u5982\u679c\u4f60\u5f88\u5173\u5fc3\u6548\u7387\u95ee\u9898\uff0c\u5f53\u4f60\u7b2c\u4e00\u6b21\u770b\u5230\u540e\u7f00increment\u51fd\u6570\u65f6, \u4f60\u53ef\u80fd\u89c9\u5f97\u6709\u4e9b\u95ee\u9898\u3002\u8fd9\u4e2a\u51fd\u6570\u5fc5\u987b\u5efa\u7acb\u4e00\u4e2a\u4e34\u65f6\u5bf9\u8c61\u4ee5\u505a\u4e3a\u5b83\u7684\u8fd4\u56de\u503c\uff0c\uff08\u53c2\u89c1\u6761\u6b3e19\uff09\uff0c\u4e0a\u8ff0\u5b9e\u73b0\u4ee3\u7801\u5efa\u7acb\u4e86\u4e00\u4e2a\u663e\u793a\u7684\u4e34\u65f6\u5bf9\u8c61\uff08oldValue\uff09\uff0c\u8fd9\u4e2a\u4e34\u65f6\u5bf9\u8c61\u5fc5\u987b\u88ab\u6784\u9020\u5e76\u5728\u6700\u540e\u88ab\u7ed3\u6784\u3002\u524d\u7f00increment\u51fd\u6570\u6ca1\u6709\u8fd9\u6837\u7684\u4e34\u65f6\u5bf9\u8c61\u3002\u7531\u6b64\u5f97\u51fa\u4e00\u4e2a\u4ee4\u4eba\u60ca\u8bb6\u7684\u7ed3\u8bba\uff0c\u5982\u679c\u4ec5\u4e3a\u4e86\u63d0\u9ad8\u4ee3\u7801\u6548\u7387\uff0cUPInt\u7684\u8c03\u7528\u8005\u5e94\u8be5\u5c3d\u91cf\u4f7f\u7528\u524d\u7f00increment\uff0c\u5c11\u7528\u540e\u7f00increment\uff0c\u9664\u975e\u786e\u5b9e\u9700\u8981\u4f7f\u7528\u540e\u7f00increment\u3002\u8ba9\u6211\u4eec\u660e\u786e\u4e00\u4e0b\uff0c\u5f53\u5904\u7406\u7528\u6237\u5b9a\u4e49\u7684\u7c7b\u578b\u65f6\uff0c\u5c3d\u53ef\u80fd\u5730\u4f7f\u7528\u524d\u7f00increment\uff0c\u56e0\u4e3a\u5b83\u7684\u6548\u7387\u8f83\u9ad8\u3002<\/p>\n

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