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c++ - 未定义的对 `MyLinkedList 的引用::MyLinkedList(int)'

问题描述

我是 C++ 新手，我尝试实现自己的链接列表，而我在以下代码中遇到了这个问题。

主文件

#include <iostream>
#include <string>
#include "headers/heder.h"

using namespace std;

int main() {


    MyLinkedList<int> integ = new MyLinkedList<int>(3);


    MyLinkedList<string> third ("Cookie", nullptr);
    MyLinkedList<string> second ("likes", &third);
    MyLinkedList<string> first ("James", &second);

    MyLinkedList<string>* selected = &first;

    while (selected->getNext() != NULL){
        cout << selected->getNext()->getValue() << " ";
        selected = selected->getNext();
    }


    return 0;
}

海德.h

template <class T>
class MyLinkedList {
    T value;
    MyLinkedList* next;

public:

    MyLinkedList *getNext() const;

    void setNext(MyLinkedList *next);

    T getValue() const;

    void setValue(T value);


    MyLinkedList(T value, MyLinkedList *next);

    MyLinkedList(T value);

    MyLinkedList(MyLinkedList *next);
};

heder.cpp


template<class T>
T MyLinkedList<T>::getValue() const {
    return value;
}

template<class T>
void MyLinkedList<T>::setValue(T value) {
    MyLinkedList::value = value;
}

template<class T>
MyLinkedList<T> *MyLinkedList<T>::getNext() const {
    return next;
}

template<class T>
void MyLinkedList<T>::setNext(MyLinkedList *next) {
    MyLinkedList::next = next;
}

template<class T>
MyLinkedList<T>::MyLinkedList(T value, MyLinkedList *next):value(value), next(next) {}

template<class T>
MyLinkedList<T>::MyLinkedList(T value):value(value) { next = NULL; }

template<class T>
MyLinkedList<T>::MyLinkedList(MyLinkedList *next): next(next) { &value = NULL; }

为什么我得到他的错误：

CMakeFiles\untitled.dir/objects.a(main.cpp.obj): In function `main':
C:/Users/mstele/CLionProjects/untitled/main.cpp:24: undefined reference to `MyLinkedList<int>::MyLinkedList(int)'
C:/Users/mstele/CLionProjects/untitled/main.cpp:24: undefined reference to `MyLinkedList<int>::MyLinkedList(MyLinkedList<int>*)'
C:/Users/mstele/CLionProjects/untitled/main.cpp:27: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::MyLinkedList(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >*)'
C:/Users/mstele/CLionProjects/untitled/main.cpp:28: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::MyLinkedList(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >*)'
C:/Users/mstele/CLionProjects/untitled/main.cpp:29: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::MyLinkedList(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >, MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >*)'
C:/Users/mstele/CLionProjects/untitled/main.cpp:33: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::getNext() const'
C:/Users/mstele/CLionProjects/untitled/main.cpp:34: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::getNext() const'
C:/Users/mstele/CLionProjects/untitled/main.cpp:34: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::getValue() const'
C:/Users/mstele/CLionProjects/untitled/main.cpp:35: undefined reference to `MyLinkedList<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::getNext() const'
collect2.exe: error: ld returned 1 exit status
mingw32-make.exe[3]: *** [CMakeFiles\untitled.dir\build.make:100: untitled.exe] Error 1
mingw32-make.exe[2]: *** [CMakeFiles\Makefile2:72: CMakeFiles/untitled.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:84: CMakeFiles/untitled.dir/rule] Error 2
mingw32-make.exe: *** [Makefile:117: untitled] Error 2

我在stackoverflow上没有找到任何类似的答案，所以如果有人能帮助我，我会很高兴。

标签： c++templatesc++14

解决方案

您必须将 heder.cpp 的全部内容移动到 heder.h 中。模板定义必须在使用它们的地方可见，即在 main.cpp 中。这与非模板函数不同。

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