\n| \u5f15\u7528\/const \u5904\u7406<\/td>\n | \u901a\u5e38\u4f1a\u5ffd\u7565\u5f15\u7528\u548c\u9876\u5c42 const<\/td>\n | \u4fdd\u7559\u5b8c\u6574\u7684\u7c7b\u578b\u4fe1\u606f<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u770b\u4e00\u4e2a\u5178\u578b\u4f8b\u5b50：<\/p>\n const int num = 1;
\nconst int& ref = num;<\/p>\n auto a = ref; \/\/ a \u7684\u7c7b\u578b\u662f int（\u53bb\u6389\u4e86 const \u548c\u5f15\u7528）
\ndecltype(ref) b = num; \/\/ b \u7684\u7c7b\u578b\u662f const int&（\u5b8c\u6574\u4fdd\u7559）<\/p>\n \u6838\u5fc3\u7406\u89e3：<\/p>\n \n- \n
auto\u00a0\u50cf\u662f\u4e00\u4e2a"\u503c\u62f7\u8d1d"\u673a\u5668，\u5b83\u4f1a\u5265\u79bb\u5f15\u7528\u548c const，\u7ed9\u4f60\u4e00\u4e2a\u5168\u65b0\u7684\u72ec\u7acb\u53d8\u91cf\u3002<\/p>\n<\/li>\n - \n
decltype\u00a0\u50cf\u662f\u4e00\u4e2a"\u7c7b\u578b\u955c\u5b50"，\u5b83\u5fe0\u5b9e\u5730\u53cd\u6620\u51fa\u539f\u59cb\u7c7b\u578b\u7684\u5168\u8c8c，\u5305\u62ec\u5f15\u7528\u548c const \u4fee\u9970\u3002<\/p>\n<\/li>\n<\/ul>\n
\n\u56db\u3001decltype \u7684\u6838\u5fc3\u4ef7\u503c：\u6a21\u677f\u4e2d\u7684\u8fd4\u56de\u7c7b\u578b\u63a8\u5bfc<\/h3>\ndecltype\u00a0\u6700\u95ea\u5149\u7684\u5e94\u7528\u573a\u666f\u662f\u5728\u6a21\u677f\u7f16\u7a0b\u4e2d，\u5f53\u8fd4\u56de\u7c7b\u578b\u4f9d\u8d56\u4e8e\u6a21\u677f\u53c2\u6570\u65f6\u3002<\/p>\n \u95ee\u9898\u573a\u666f<\/h4>\n\u5047\u8bbe\u6211\u4eec\u8981\u5199\u4e00\u4e2a\u51fd\u6570，\u8fd4\u56de\u5bb9\u5668\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u7684\u5f15\u7528，\u4ee5\u4fbf\u53ef\u4ee5\u4fee\u6539\u5bb9\u5668\u5185\u7684\u5143\u7d20：<\/p>\n int& getFirst(std::vector<int>& container) {
\n return container.front();
\n}<\/p>\n \u4f46\u8fd9\u4e2a\u51fd\u6570\u53ea\u80fd\u5904\u7406\u00a0std::vector<int>，\u65e0\u6cd5\u5904\u7406\u00a0std::vector<double>\u3001std::list<int>\u3001std::string\u00a0\u7b49\u5176\u4ed6\u7c7b\u578b\u3002<\/p>\n \u5c1d\u8bd5\u7528\u6a21\u677f\u89e3\u51b3（\u9519\u8bef\u5199\u6cd5）<\/h4>\ntemplate <typename Container>
\ndecltype(container.front()) getFirst(Container& container) {
\n return container.front();
\n}<\/p>\n \u8fd9\u6bb5\u4ee3\u7801\u7f16\u8bd1\u4f1a\u5931\u8d25！\u00a0\u539f\u56e0\u662f：<\/p>\n \u7f16\u8bd1\u5668\u5728\u89e3\u6790\u8fd4\u56de\u7c7b\u578b\u00a0decltype(container.front())\u00a0\u65f6，\u8fd8\u6ca1\u6709\u770b\u5230\u53c2\u6570\u5217\u8868\u4e2d\u7684\u00a0Container& container，\u4e5f\u5c31\u662f\u8bf4\u6b64\u65f6\u00a0container\u00a0\u8fd8\u672a\u58f0\u660e，\u7f16\u8bd1\u5668\u6839\u672c\u4e0d\u77e5\u9053\u00a0container\u00a0\u662f\u4ec0\u4e48\u3002<\/p>\n \u89e3\u51b3\u65b9\u6848：\u5c3e\u7f6e\u8fd4\u56de\u7c7b\u578b（Trailing Return Type）<\/h4>\nC++11 \u5f15\u5165\u4e86"\u5c3e\u7f6e\u8fd4\u56de\u7c7b\u578b"\u8bed\u6cd5，\u5c06\u8fd4\u56de\u7c7b\u578b\u653e\u5230\u51fd\u6570\u53c2\u6570\u5217\u8868\u4e4b\u540e：<\/p>\n template <typename Container>
\nauto getFirst(Container& container) -> decltype(container.front()) {
\n return container.front();
\n}<\/p>\n \u8bed\u6cd5\u683c\u5f0f：<\/p>\n auto \u51fd\u6570\u540d(\u53c2\u6570\u5217\u8868) -> \u8fd4\u56de\u7c7b\u578b<\/p>\n \u8fd9\u6837，\u5f53\u7f16\u8bd1\u5668\u89e3\u6790\u5230\u00a0decltype(container.front())\u00a0\u65f6，container\u00a0\u5df2\u7ecf\u5728\u53c2\u6570\u5217\u8868\u4e2d\u58f0\u660e\u4e86，\u7c7b\u578b\u63a8\u5bfc\u5c31\u53ef\u4ee5\u987a\u5229\u8fdb\u884c\u3002<\/p>\n
\n\u4e94\u3001decltype \u6700\u6613\u51fa\u9519\u7684\u5730\u65b9：\u62ec\u53f7\u9677\u9631<\/h3>\n\u8fd9\u662f\u00a0decltype\u00a0\u4e2d\u6700\u91cd\u8981\u3001\u4e5f\u6700\u8ba9\u4eba\u8ff7\u60d1\u7684\u89c4\u5219\u3002<\/p>\n int num = 10;<\/p>\n decltype(num) a = 20; \/\/ int
\ndecltype((num)) b = num; \/\/ int&<\/p>\n \u4ec5\u4ec5\u591a\u4e86\u4e00\u5c42\u62ec\u53f7，\u7c7b\u578b\u5c31\u5b8c\u5168\u4e0d\u540c\u4e86！<\/p>\n \u4e3a\u4ec0\u4e48？<\/h4>\ndecltype\u00a0\u5bf9\u62ec\u53f7\u7684\u5904\u7406\u9075\u5faa\u4e24\u6761\u6838\u5fc3\u89c4\u5219：<\/p>\n \u89c4\u5219\u4e00：\u76f4\u63a5\u5199\u53d8\u91cf\u540d<\/p>\n \u5982\u679c\u62ec\u53f7\u5185\u76f4\u63a5\u662f\u4e00\u4e2a\u53d8\u91cf\u540d（\u4e0d\u662f\u8868\u8fbe\u5f0f），decltype\u00a0\u8fd4\u56de\u8be5\u53d8\u91cf\u58f0\u660e\u65f6\u7684\u7c7b\u578b\u3002<\/p>\n int num = 10;
\nconst int count = 20;
\nint& ref = num;<\/p>\n decltype(num) \/\/ int
\ndecltype(count) \/\/ const int
\ndecltype(ref) \/\/ int&<\/p>\n \u89c4\u5219\u4e8c：\u653e\u5165\u7684\u662f\u666e\u901a\u8868\u8fbe\u5f0f<\/p>\n \u5982\u679c\u62ec\u53f7\u5185\u662f\u4e00\u4e2a\u8868\u8fbe\u5f0f（\u5305\u62ec\u5e26\u62ec\u53f7\u7684\u53d8\u91cf\u540d，\u5982\u00a0(num)），\u5219\u6839\u636e\u8868\u8fbe\u5f0f\u7684\u503c\u7c7b\u522b\u6765\u5224\u65ad：<\/p>\n \n\u8868\u8fbe\u5f0f\u7c7b\u522bdecltype\u00a0\u63a8\u5bfc\u7c7b\u578b\u793a\u4f8b<\/tr>\n \n\n| \u5de6\u503c\u8868\u8fbe\u5f0f<\/td>\n | T&<\/td>\n | decltype((num))\u00a0\u2192\u00a0int&<\/td>\n<\/tr>\n | \n| \u5c06\u4ea1\u503c\u8868\u8fbe\u5f0f<\/td>\n | T&&<\/td>\n | decltype(std::move(num))\u00a0\u2192\u00a0int&&<\/td>\n<\/tr>\n | \n| \u7eaf\u53f3\u503c\u8868\u8fbe\u5f0f<\/td>\n | T<\/td>\n | decltype(42)\u00a0\u2192\u00a0int<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u53d8\u91cf\u540d\u00a0num\u00a0\u5355\u72ec\u51fa\u73b0\u65f6，\u88ab\u89c6\u4e3a"\u53d8\u91cf\u58f0\u660e\u67e5\u8be2"，\u800c\u4e0d\u662f\u8868\u8fbe\u5f0f，\u6240\u4ee5\u8d70\u7684\u662f\u89c4\u5219\u4e00\u3002<\/p>\n \u5f53\u5199\u6210\u00a0(num)\u00a0\u65f6，\u5b83\u88ab\u770b\u4f5c\u4e00\u4e2a\u5de6\u503c\u8868\u8fbe\u5f0f，\u56e0\u6b64\u00a0decltype((num))\u00a0\u63a8\u5bfc\u4e3a\u00a0int&\u3002<\/p>\n \u8fd9\u5c31\u89e3\u91ca\u4e86\u4e3a\u4ec0\u4e48：<\/p>\n \n- \n
decltype(num)\u00a0\u2192\u00a0int（\u76f4\u63a5\u67e5\u58f0\u660e）<\/p>\n<\/li>\n - \n
decltype((num))\u00a0\u2192\u00a0int&（\u5de6\u503c\u8868\u8fbe\u5f0f\u89c4\u5219）<\/p>\n<\/li>\n<\/ul>\n
\n\u516d\u3001decltype(auto)：C++14 \u7684\u589e\u5f3a<\/h3>\nC++14 \u5f15\u5165\u4e86\u00a0decltype(auto)，\u5b83\u7ed3\u5408\u4e86\u00a0auto\u00a0\u7684\u8bed\u6cd5\u4fbf\u5229\u6027\u548c\u00a0decltype\u00a0\u7684\u63a8\u5bfc\u89c4\u5219\u3002<\/p>\n \u57fa\u672c\u7528\u6cd5<\/h4>\nint num = 10;
\nint& ref = num;<\/p>\n auto a = ref; \/\/ int（auto \u5265\u79bb\u5f15\u7528）
\ndecltype(auto) b = ref; \/\/ int&（\u4f7f\u7528 decltype \u89c4\u5219）<\/p>\n decltype(auto)\u00a0\u7684\u4f5c\u7528\u662f：\u7528\u00a0decltype\u00a0\u7684\u89c4\u5219\u6765\u63a8\u5bfc\u00a0auto\u00a0\u8981\u4f7f\u7528\u7684\u7c7b\u578b\u3002<\/p>\n \u5178\u578b\u5e94\u7528：\u7b80\u5316\u6a21\u677f\u8fd4\u56de\u7c7b\u578b<\/h4>\nC++11 \u7684\u5c3e\u7f6e\u8fd4\u56de\u7c7b\u578b\u5199\u6cd5：<\/p>\n template<typename Container>
\nauto getFirst(Container& container) -> decltype(container.front()) {
\n return container.front();
\n}<\/p>\n C++14 \u53ef\u4ee5\u7b80\u5316\u4e3a：<\/p>\n template<typename Container>
\ndecltype(auto) getFirst(Container& container) {
\n return container.front();
\n}<\/p>\n decltype(auto)\u00a0\u4f1a\u4fdd\u7559\u00a0container.front()\u00a0\u7684\u5b8c\u6574\u7c7b\u578b（\u5305\u62ec\u5f15\u7528），\u56e0\u6b64\u8fd4\u56de\u7684\u662f\u5f15\u7528，\u53ef\u4ee5\u7528\u4e8e\u4fee\u6539\u5bb9\u5668\u5143\u7d20\u3002<\/p>\n \u5b9e\u9645\u6848\u4f8b\u6f14\u793a<\/h4>\n#include <iostream>
\n#include <vector><\/p>\n template<typename Container>
\ndecltype(auto) getElement(Container& container, std::size_t index) {
\n return container[index];
\n}<\/p>\n int main() {
\n std::vector<int> nums = {10, 20, 30};
\n getElement(nums, 1) = 100; \/\/ \u53ef\u4ee5\u4fee\u6539！\u56e0\u4e3a\u8fd4\u56de\u7684\u662f int&
\n std::cout << nums[1]; \/\/ \u8f93\u51fa 100<\/p>\n const std::vector<int> const_nums = {10, 20, 30};
\n getElement(const_nums, 1) = 100; \/\/ \u7f16\u8bd1\u9519\u8bef！\u8fd4\u56de const int&，\u4e0d\u53ef\u4fee\u6539
\n return 0;
\n}<\/p>\n
\n\u4e03\u3001decltype(auto) \u7684\u5371\u9669\u9677\u9631：\u60ac\u7a7a\u5f15\u7528<\/h3>\n\u4f7f\u7528\u00a0decltype(auto)\u00a0\u65f6\u5fc5\u987b\u7279\u522b\u5c0f\u5fc3\u62ec\u53f7\u9677\u9631：<\/p>\n decltype(auto) getValue() {
\n int num = 10;
\n return (num); \/\/ \u5371\u9669！
\n}<\/p>\n \u7531\u4e8e\u00a0(num)\u00a0\u662f\u5de6\u503c\u8868\u8fbe\u5f0f，decltype(auto)\u00a0\u63a8\u5bfc\u4e3a\u00a0int&，\u51fd\u6570\u8fd4\u56de\u7684\u662f\u5c40\u90e8\u53d8\u91cf\u00a0num\u00a0\u7684\u5f15\u7528\u3002<\/p>\n \u4f46\u00a0num\u00a0\u662f\u6808\u4e0a\u7684\u5c40\u90e8\u53d8\u91cf，\u51fd\u6570\u8fd4\u56de\u540e\u5373\u88ab\u9500\u6bc1，\u8fd9\u4e2a\u5f15\u7528\u5c31\u53d8\u6210\u4e86\u60ac\u7a7a\u5f15\u7528（dangling reference），\u8bbf\u95ee\u5b83\u5c06\u5bfc\u81f4\u672a\u5b9a\u4e49\u884c\u4e3a\u3002<\/p>\n \u6b63\u786e\u5199\u6cd5：<\/p>\n decltype(auto) getValue() {
\n int num = 10;
\n return num; \/\/ \u8fd4\u56de int（\u503c\u62f7\u8d1d），\u5b89\u5168
\n}<\/p>\n \u7ecf\u9a8c\u6cd5\u5219：\u00a0\u4f7f\u7528\u00a0decltype(auto)\u00a0\u4f5c\u4e3a\u8fd4\u56de\u7c7b\u578b\u65f6，\u786e\u4fdd\u00a0return\u00a0\u8bed\u53e5\u540e\u76f4\u63a5\u8ddf\u53d8\u91cf\u540d，\u4e0d\u8981\u52a0\u62ec\u53f7，\u9664\u975e\u4f60\u6e05\u695a\u5730\u77e5\u9053\u81ea\u5df1\u5728\u505a\u4ec0\u4e48\u3002<\/p>\n
\n\u516b\u3001\u7a7a\u5bb9\u5668\u7684\u5b89\u5168\u95ee\u9898<\/h3>\n\u65e0\u8bba\u4f7f\u7528\u54ea\u79cd\u5199\u6cd5，\u8c03\u7528\u00a0container.front()\u00a0\u6216\u00a0container[0]\u00a0\u524d\u90fd\u5fc5\u987b\u786e\u4fdd\u5bb9\u5668\u975e\u7a7a：<\/p>\n template<typename Container>
\nauto getFirst(Container& container) -> decltype(container.front()) {
\n return container.front(); \/\/ \u5982\u679c container \u4e3a\u7a7a，\u672a\u5b9a\u4e49\u884c\u4e3a！
\n}<\/p>\n \u5b89\u5168\u7248\u672c：<\/p>\n #include <stdexcept><\/p>\n template<typename Container>
\nauto getFirst(Container& container) -> decltype(container.front()) {
\n if (container.empty()) {
\n throw std::out_of_range("\u5bb9\u5668\u4e3a\u7a7a");
\n }
\n return container.front();
\n}<\/p>\n
\n\u4e5d\u3001\u5e38\u89c1\u63a8\u5bfc\u7ed3\u679c\u901f\u67e5\u8868<\/h3>\n\n\u4ee3\u7801\u63a8\u5bfc\u7c7b\u578b<\/tr>\n \n\n| decltype(num)\u00a0\u5176\u4e2d\u00a0num\u00a0\u662f\u00a0int<\/td>\n | int<\/td>\n<\/tr>\n | \n| decltype((num))\u00a0\u5176\u4e2d\u00a0num\u00a0\u662f\u00a0int<\/td>\n | int&<\/td>\n<\/tr>\n | \n| decltype(count)\u00a0\u5176\u4e2d\u00a0count\u00a0\u662f\u00a0const int<\/td>\n | const int<\/td>\n<\/tr>\n | \n| decltype((count))\u00a0\u5176\u4e2d\u00a0count\u00a0\u662f\u00a0const int<\/td>\n | const int&<\/td>\n<\/tr>\n | \n| decltype(ref)\u00a0\u5176\u4e2d\u00a0ref\u00a0\u662f\u00a0int&<\/td>\n | int&<\/td>\n<\/tr>\n | \n| decltype((ref))\u00a0\u5176\u4e2d\u00a0ref\u00a0\u662f\u00a0int&<\/td>\n | int&<\/td>\n<\/tr>\n | \n| decltype(42)<\/td>\n | int<\/td>\n<\/tr>\n | \n| decltype(num + 10)<\/td>\n | int<\/td>\n<\/tr>\n | \n| decltype(std::move(num))<\/td>\n | int&&<\/td>\n<\/tr>\n | \n| decltype(getValue())\u00a0\u5176\u4e2d\u00a0getValue()\u00a0\u8fd4\u56de\u00a0int<\/td>\n | int<\/td>\n<\/tr>\n | \n| decltype(getRef())\u00a0\u5176\u4e2d\u00a0getRef()\u00a0\u8fd4\u56de\u00a0int&<\/td>\n | int&<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n\u5341\u3001\u603b\u7ed3\u4e0e\u6700\u4f73\u5b9e\u8df5<\/h3>\n\u6838\u5fc3\u8981\u70b9<\/h4>\n- \n
decltype\u00a0\u53ea\u505a\u7c7b\u578b\u67e5\u8be2，\u4e0d\u6267\u884c\u8868\u8fbe\u5f0f\u00a0\u2014 \u5b83\u662f\u7eaf\u7f16\u8bd1\u671f\u884c\u4e3a\u3002<\/p>\n<\/li>\n - \n
auto\u00a0vs\u00a0decltype\u00a0\u2014\u00a0auto\u00a0\u5265\u79bb\u5f15\u7528\u548c const，decltype\u00a0\u5b8c\u6574\u4fdd\u7559\u3002<\/p>\n<\/li>\n - \n
\u62ec\u53f7\u9677\u9631\u00a0\u2014\u00a0decltype((var))\u00a0\u662f\u00a0T&（\u5de6\u503c\u8868\u8fbe\u5f0f），decltype(var)\u00a0\u662f\u00a0T（\u67e5\u58f0\u660e）\u3002<\/p>\n<\/li>\n - \n
\u6a21\u677f\u4e2d\u8fd4\u56de\u7c7b\u578b\u63a8\u5bfc\u00a0\u2014 \u4f18\u5148\u4f7f\u7528 C++14 \u7684\u00a0decltype(auto)\u00a0\u6216 C++11 \u7684\u5c3e\u7f6e\u8fd4\u56de\u7c7b\u578b\u3002<\/p>\n<\/li>\n - \n
decltype(auto)\u00a0\u52a0\u62ec\u53f7\u8fd4\u56de\u5c40\u90e8\u53d8\u91cf\u662f\u5371\u9669\u7684\u00a0\u2014 \u4f1a\u4ea7\u751f\u60ac\u7a7a\u5f15\u7528\u3002<\/p>\n<\/li>\n \u6700\u4f73\u5b9e\u8df5<\/h4>\n\n- \n
\u5728\u6a21\u677f\u4e2d\u9700\u8981\u4fdd\u7559\u5f15\u7528\u65f6，\u4f7f\u7528\u00a0decltype(auto)\u00a0\u6216\u5c3e\u7f6e\u8fd4\u56de\u7c7b\u578b\u3002<\/p>\n<\/li>\n - \n
\u4f7f\u7528\u00a0decltype((var))\u00a0\u65f6，\u786e\u4fdd\u4f60\u5bf9\u5de6\u503c\u8868\u8fbe\u5f0f\u7684\u89c4\u5219\u6709\u6e05\u6670\u7406\u89e3\u3002<\/p>\n<\/li>\n - \n
\u907f\u514d\u5728\u00a0decltype(auto)\u00a0\u7684\u00a0return\u00a0\u8bed\u53e5\u4e2d\u52a0\u62ec\u53f7，\u9664\u975e\u4f60\u660e\u786e\u9700\u8981\u8fd4\u56de\u5f15\u7528\u3002<\/p>\n<\/li>\n - \n
\u59cb\u7ec8\u68c0\u67e5\u5bb9\u5668\u662f\u5426\u4e3a\u7a7a，\u518d\u8c03\u7528\u00a0front()\u00a0\u6216\u00a0operator[]\u3002<\/p>\n<\/li>\n<\/ul>\n decltype\u00a0\u662f C++ \u7c7b\u578b\u7cfb\u7edf\u4e2d\u7684\u4e00\u628a\u7cbe\u5de7\u7684\u624b\u672f\u5200，\u7528\u5f97\u597d\u53ef\u4ee5\u5927\u5e45\u63d0\u5347\u4ee3\u7801\u7684\u901a\u7528\u6027\u548c\u5b89\u5168\u6027，\u4f46\u4e5f\u9700\u8981\u5bf9\u5176\u89c4\u5219\u6709\u6df1\u5165\u7684\u7406\u89e3\u3002\u5e0c\u671b\u672c\u6587\u80fd\u5e2e\u52a9\u4f60\u907f\u5f00\u5e38\u89c1\u7684\u9677\u9631，\u5199\u51fa\u66f4\u4f18\u96c5\u3001\u66f4\u5b89\u5168\u7684 C++ \u4ee3\u7801\u3002<\/p>\n","protected":false},"excerpt":{"rendered":" \u5f15\u8a00：\u4ec0\u4e48\u662f decltype？\u5728 C11 \u5f15\u5165\u7684\u4f17\u591a\u65b0\u7279\u6027\u4e2d，decltype\u00a0\u662f\u4e00\u4e2a\u76f8\u5bf9\u4f4e\u8c03\u5374\u6781\u5176\u5f3a\u5927\u7684\u5de5\u5177\u3002\u5b83\u7684\u540d\u5b57\u6765\u6e90\u4e8e\u00a0\\”declared type\\”（\u58f0\u660e\u7c7b\u578b），\u6838\u5fc3\u529f\u80fd\u975e\u5e38\u7b80\u5355：\u8ba9\u7f16\u8bd1\u5668\u5e2e\u4f60\u67e5\u8be2\u67d0\u4e2a\u53d8\u91cf\u6216\u8868\u8fbe\u5f0f\u7684\u7c7b\u578b\u3002\u57fa\u672c\u8bed\u6cd5：decltype(\u53d8\u91cf\u6216\u8868\u8fbe\u5f0f) \u65b0\u53d8\u91cf\u540d;\u6765\u770b\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u4f8b\u5b50：int num 1;
\ndecltype(nu<\/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],"topic":[],"class_list":["post-100656","post","type-post","status-publish","format-standard","hentry","category-server","tag-c"],"yoast_head":"\n \u6df1\u5165\u7406\u89e3 C++11 decltype\uff1a\u7c7b\u578b\u63a8\u5bfc\u7684\u5229\u5668\u4e0e\u9677\u9631 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/100656.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"\u6df1\u5165\u7406\u89e3 C++11 decltype\uff1a\u7c7b\u578b\u63a8\u5bfc\u7684\u5229\u5668\u4e0e\u9677\u9631 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"\u5f15\u8a00：\u4ec0\u4e48\u662f decltype？\u5728 C11 \u5f15\u5165\u7684\u4f17\u591a\u65b0\u7279\u6027\u4e2d，decltype\u00a0\u662f\u4e00\u4e2a\u76f8\u5bf9\u4f4e\u8c03\u5374\u6781\u5176\u5f3a\u5927\u7684\u5de5\u5177\u3002\u5b83\u7684\u540d\u5b57\u6765\u6e90\u4e8e\u00a0"declared type"（\u58f0\u660e\u7c7b\u578b），\u6838\u5fc3\u529f\u80fd\u975e\u5e38\u7b80\u5355：\u8ba9\u7f16\u8bd1\u5668\u5e2e\u4f60\u67e5\u8be2\u67d0\u4e2a\u53d8\u91cf\u6216\u8868\u8fbe\u5f0f\u7684\u7c7b\u578b\u3002\u57fa\u672c\u8bed\u6cd5：decltype(\u53d8\u91cf\u6216\u8868\u8fbe\u5f0f) \u65b0\u53d8\u91cf\u540d;\u6765\u770b\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u4f8b\u5b50：int num 1; 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decltype(nu","og_url":"https:\/\/www.wsisp.com\/helps\/100656.html","og_site_name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","article_published_time":"2026-09-04T17:40:55+00:00","author":"admin","twitter_card":"summary_large_image","twitter_misc":{"\u4f5c\u8005":"admin","\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4":"4 \u5206"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"WebPage","@id":"https:\/\/www.wsisp.com\/helps\/100656.html","url":"https:\/\/www.wsisp.com\/helps\/100656.html","name":"\u6df1\u5165\u7406\u89e3 C++11 decltype\uff1a\u7c7b\u578b\u63a8\u5bfc\u7684\u5229\u5668\u4e0e\u9677\u9631 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","isPartOf":{"@id":"https:\/\/www.wsisp.com\/helps\/#website"},"datePublished":"2026-09-04T17:40:55+00:00","dateModified":"2026-09-04T17:40:55+00:00","author":{"@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41"},"breadcrumb":{"@id":"https:\/\/www.wsisp.com\/helps\/100656.html#breadcrumb"},"inLanguage":"zh-Hans","potentialAction":[{"@type":"ReadAction","target":["https:\/\/www.wsisp.com\/helps\/100656.html"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/www.wsisp.com\/helps\/100656.html#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"\u9996\u9875","item":"https:\/\/www.wsisp.com\/helps"},{"@type":"ListItem","position":2,"name":"\u6df1\u5165\u7406\u89e3 C++11 decltype\uff1a\u7c7b\u578b\u63a8\u5bfc\u7684\u5229\u5668\u4e0e\u9677\u9631"}]},{"@type":"WebSite","@id":"https:\/\/www.wsisp.com\/helps\/#website","url":"https:\/\/www.wsisp.com\/helps\/","name":"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3","description":"\u9999\u6e2f\u670d\u52a1\u5668_\u9999\u6e2f\u4e91\u670d\u52a1\u5668\u8d44\u8baf_\u670d\u52a1\u5668\u5e2e\u52a9\u6587\u6863_\u670d\u52a1\u5668\u6559\u7a0b","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/www.wsisp.com\/helps\/?s={search_term_string}"},"query-input":"required name=search_term_string"}],"inLanguage":"zh-Hans"},{"@type":"Person","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/358e386c577a3ab51c4493330a20ad41","name":"admin","image":{"@type":"ImageObject","inLanguage":"zh-Hans","@id":"https:\/\/www.wsisp.com\/helps\/#\/schema\/person\/image\/","url":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","contentUrl":"https:\/\/gravatar.wp-china-yes.net\/avatar\/?s=96&d=mystery","caption":"admin"},"sameAs":["http:\/\/wp.wsisp.com"],"url":"https:\/\/www.wsisp.com\/helps\/author\/admin"}]}},"_links":{"self":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/100656","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/comments?post=100656"}],"version-history":[{"count":0,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/posts\/100656\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/media?parent=100656"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/categories?post=100656"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/tags?post=100656"},{"taxonomy":"topic","embeddable":true,"href":"https:\/\/www.wsisp.com\/helps\/wp-json\/wp\/v2\/topic?post=100656"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}} | | |