模板 class 无法识别模板参数

Question

我正在尝试编译以下代码。但是，由于某种原因，编译失败了。有很多错误，但都与模板中的TYPE有关。

我检查了代码，它看起来像。我看不出问题所在。这可能是一个愚蠢的错误，但不要看。有人可以帮忙吗？

头文件：

namespace rca {

template<class ContainerType>
class SteinerTreeObserver {

public:
    SteinerTreeObserver();
    SteinerTreeObserver(ContainerType & ec, STTree & st, int);

    void set_steiner_tree (STTree &st, int);
    STTree & get_steiner_tree ();

    void set_container (ContainerType & ec);
    ContainerType & get_container ();

    bool add_edge (int, int, int, int);

    void prunning (int, int);

private:
      ContainerType m_ec;
      STTree m_st;  
      DisjointSet2 dset;

};

};

这是 cpp 文件：

#include "steiner_tree_observer.h"

using namespace rca;

template<class ContainerType>
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(){}

SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes){}

template<class ContainerType>
void SteinerTreeObserver<ContainerType>::set_steiner_tree (STTree & st, int nodes){}

template<class ContainerType>
STTree & SteinerTreeObserver<ContainerType>::get_steiner_tree ()
{ return m_st;}

void SteinerTreeObserver<ContainerType>::set_container (ContainerType & ec) 
{}

ContainerType & SteinerTreeObserver<ContainerType>::get_container () 
{return m_ec;}

template<class ContainerType>
bool SteinerTreeObserver<ContainerType>::add_edge (int x, 
                                               int y, 
                                               int cost, 
                                               int band_usage)
{ return true;}


template<class ContainerType>
void SteinerTreeObserver<ContainerType>::prunning (int rest, int band)
{}

template class SteinerTreeObserver<EdgeContainer<Comparator, HCell>>;

输出：

steiner_tree_observer.cpp: At global scope:
steiner_tree_observer.cpp:10:21: error: ‘ContainerType’ was not declared in this scope
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                 ^
steiner_tree_observer.cpp:10:34: error: template argument 1 is invalid
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                              ^
steiner_tree_observer.cpp:10:56: error: invalid type in declaration before ‘(’ token
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                    ^
steiner_tree_observer.cpp:10:57: error: ‘ContainerType’ was not declared in this scope
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                     ^
steiner_tree_observer.cpp:10:73: error: ‘ec’ was not declared in this scope
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                                         ^
steiner_tree_observer.cpp:10:83: error: expected primary-expression before ‘&’ token
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                                                ^
steiner_tree_observer.cpp:10:85: error: ‘st’ was not declared in this scope
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                                                  ^
steiner_tree_observer.cpp:10:88: error: expected primary-expression before ‘int’
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                                                    ^
steiner_tree_observer.cpp:10:97: error: expression list treated as compound expression in initializer [-fpermissive]
SteinerTreeObserver<ContainerType>::SteinerTreeObserver(ContainerType & ec,STTree & st,int nodes)
                                                                                             ^
steiner_tree_observer.cpp:11:1: error: expected ‘,’ or ‘;’ before ‘{’ token {

steiner_tree_observer.cpp:18:25: error: expected initializer before ‘<’ token
void SteinerTreeObserver<ContainerType>::set_steiner_tree (STTree & st, int nodes)
                       ^
steiner_tree_observer.cpp:25:29: error: expected initializer before ‘<’ token
STTree & SteinerTreeObserver<ContainerType>::get_steiner_tree ()
                           ^
steiner_tree_observer.cpp:30:25: error: expected initializer before ‘<’ token
void SteinerTreeObserver<ContainerType>::set_container (ContainerType & ec) 
                        ^
steiner_tree_observer.cpp:35:1: error: ‘ContainerType’ does not name a type
ContainerType & SteinerTreeObserver<ContainerType>::get_container () 
 ^
steiner_tree_observer.cpp:41:25: error: expected initializer before ‘<’ token
bool SteinerTreeObserver<ContainerType>::add_edge (int x, 
                     ^
steiner_tree_observer.cpp:64:25: error: expected initializer before ‘<’ token
void SteinerTreeObserver<ContainerType>::prunning (int rest, int band)

Answer 1

好的。但是我已经在 CPP 文件中进行了显式实例化。那怎么了？ – Romerito 3 小时前您在哪里进行了显式实例化？

您必须在 header (#include "steiner_tree_observer.cpp") 中包含您的 cpp 并将它们从构建中排除，并从 header。那是因为 templates-functions-definitions 在它们被实例化时总是必须知道，不像非 template-functions/classes.

顺便说一句。如果导出 class，template-classes 的显式实例化才有意义。所以你可以肯定，你的链接器将从你编译的 DLL 或 Lib 中取出符号。

模板 class 无法识别模板参数

template class does not recnognize template argument

c++

templates

compilation

g++4.8