c++ - 元编程中最后一次递归的问题

我在一个类中有以下（部分）代码，在该类中，我尝试通过C ++ 11中的元编程针对值列表评估值。bool eval(GLenum value){ return false;};template<GLenum One, GLenum... Others>bool eval(GLenum value){ if( value == One ) return true; // Try out the rest return eval<Others...>(value);};gcc抱怨：  ../emul/GLPart.h：在成员函数“ bool”中  GLPart :: eval（GLenum）[with unsigned int One = 519u，  unsigned int ... Others = {}，unsigned int ... ValidEnums = {512u，513u，  514u，515u，516u，517u，518u，519u}，GLenum = unsigned int]’：  ../emul/GLPart.h:26:31：从'bool实例化  GLPart :: eval（GLenum）[with unsigned int One = 518u，  unsigned int ... Others = {519u}，unsigned int ... ValidEnums = {512u，  513u，514u，515u，516u，517u，518u，519u}，GLenum = unsigned int]’  ../emul/GLPart.h:26:31：从'bool实例化  GLPart :: eval（GLenum）[with unsigned int One = 517u，  unsigned int ... Others = {518u，519u}，unsigned int ... ValidEnums =  {512u，513u，514u，515u，516u，517u，518u，519u}，GLenum =无符号  int]” ../emul/GLPart.h:26:31：从“ bool”实例化  GLPart :: eval（GLenum）[with unsigned int One = 516u，  unsigned int ... Others = {517u，518u，519u}，unsigned int  ... ValidEnums = {512u，513u，514u，515u，516u，517u，518u，519u}，  GLenum = unsigned int]’../emul/GLPart.h:26:31：实例化为  ‘bool GLPart :: eval（GLenum）[with unsigned int One = 515u，  unsigned int ... Others = {516u，517u，518u，519u}，unsigned int  ... ValidEnums = {512u，513u，514u，515u，516u，517u，518u，519u}，  GLenum = unsigned int]’../emul/GLPart.h:26:31：实例化为  ‘bool GLPart :: eval（GLenum）[，其中unsigned int One = 514u，  unsigned int ... Others = {515u，516u，517u，518u，519u}，unsigned int  ... ValidEnums = {512u，513u，514u，515u，516u，517u，518u，519u}，  GLenum = unsigned int]’../emul/GLPart.h:26:31：实例化为  ‘bool GLPart :: eval（GLenum）[with unsigned int One = 513u，  unsigned int ... Others = {514u，515u，516u，517u，518u，519u}，  unsigned int ... ValidEnums = {512u，513u，514u，515u，516u，517u，  518u，519u}，GLenum = unsigned int]’../emul/GLPart.h:26:31：  从'bool GLPart :: eval（GLenum）[  unsigned int一个= 512u，unsigned int ...其他= {513u，514u，515u，  516u，517u，518u，519u}，无符号整数... ValidEnums = {512u，513u，  514u，515u，516u，517u，518u，519u}，GLemum = unsigned int]’  ../emul/GLPart.h:31:43：从'bool实例化  GLPart :: Evaluate（GLenum）[具有未签名的int ... ValidEnums  = {512u，513u，514u，515u，516u，517u，518u，519u}，GLenum =无符号  int]’alpha.cpp：8：7：从此处实例化../emul/GLPart.h:26:31：  错误：没有匹配的函数可以调用‘GLPart   515u，516u，517u，518u，519u> :: eval（GLenum＆）’因此，当“一个”具有值而“其他”不具有值时，它似乎在上次递归时感到窒息。在这种情况下，模板参数应为空。我是否需要以其他方式声明普通评估？有一阵子没有编码C ++了，所以它可能微不足道，但我只是不明白;）当尝试将template 添加到第一个评估中时，它会阻塞：  ../emul/GLPart.h:14:11：错误：  非命名空间范围“ class GLPart” ../emul/GLPart.h:21:7：  错误：模板参数列表太多../emul/GLPart.h：成员中  函数“ bool GLPart :: Evaluate（GLenum）”：  ../emul/GLPart.h:32:23：错误：参数包未使用  ‘...’：../ emul / GLPart.h：32：23：注意：“ ValidEnums”  ../emul/GLPart.h:32:33：错误：在“ ...”令牌之前应为“，”或“;”解：template<GLenum One>bool eval(GLenum value){ return value == One;};template<GLenum One, GLenum Two, GLenum... Others>bool eval(GLenum value){ if( eval<One>(value) ) return true; // Try out the rest return eval<Two, Others...>(value);}; (adsbygoogle = window.adsbygoogle || []).push({}); 最佳答案 由于这往往会产生许多歧义错误，因此似乎毫无歧义的变化看起来像这样：template<GLenum One>bool eval(GLenum value){ return value == One;};template<GLenum One, GLenum Two, GLenum... Others>bool eval(GLenum value){ if( value == One ) return true; // Try out the rest return eval<Two, Others...>(value);};第一个重载仅使用一个参数，第二个重载至少使用两个参数。无论如何，接受零参数可能毫无意义。关于c++ - 元编程中最后一次递归的问题，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/7134003/ (adsbygoogle = window.adsbygoogle || []).push({});