我一直在与一个令人沮丧的错误斗争，已经花费了相当长的时间。
在将数据类型从 int 改为使用模板之前，我的程序正常运行。以下是我收到的错误信息：
g++ -c UseList.cpp
g++ -c List.cpp
g++ UseList.o List.o -o UseList
UseList.o: In function `main':
UseList.cpp:(.text+0xee): undefined reference to `List<int>::addtofront(int)'
UseList.cpp:(.text+0x10b): undefined reference to `List<int>::show()'
collect2: ld returned 1 exit status
make: *** [UseList] Error 1
以下是我代码的相关部分。请告诉我可能是什么原因。我完全不知道。谢谢！
UseList.cpp:
#include <iostream>
#include <cstdlib>
#include "List.h"
using namespace std;
int main (int argc, char *argv[]) {
cout << "-----------------------------------------" << endl;
cout << "----------------LIST ONE-----------------" << endl;
cout << "-----------------------------------------" << endl;
List<int> *list1;
srand(time(NULL));
cout << "# Add 3 random ints to the front:" << endl;
for(int i=0;i<3;i++){
list1->addtofront(rand() % 10000);
}
list1->show();
}
List.h
#include <iostream>
using namespace std;
#ifndef LIST
#define LIST
template <class L>
class Node {
public:
// constructors and destructors
Node<L>(L data);
Node();
Node<L>(const Node<L> &n);
// components of a node
L data;
Node *next;
Node *prev;
};
template <class L>
class List
{
private:
Node<L> *first;
Node<L> *last;
int num_elements;
public:
// constructors and destructors
List();
~List();
List<L>(const List<L> &l);
List *addtofront(L);
void show();
[...] // unnecessary code removed
};
// #include "List.cpp"
#endif
List.cpp
#include "List.h"
using namespace std;
// -------------------------------------
// ------------Node class---------------
// -------------------------------------
template <class L>
Node<L>::Node(L data_input) {
data = data_input;
next = 0;
prev = 0;
}
template <class L>
Node<L>::Node() {}
template <class L>
Node<L>::Node(const Node<L> &n) {
data = n.data;
next = n.next;
prev = n.prev;
}
// -------------------------------------
// ------------List class---------------
// -------------------------------------
template <class L>
List<L>::List() {
first = NULL;
last = NULL;
num_elements = 0;
}
template <class L>
// Appends data to the front of the list.
List<L> *List<L>::addtofront(L data) {
Node<L> *new_node = new Node<L>(data);
if(first == 0 && last == 0) {
first = new_node;
last = new_node;
} else {
// there will be no previous since
// it is the first
new_node->next = first;
first->prev = new_node;
first = new_node;
}
num_elements++;
}
template <class L>
// Append data to the end of the list.
List<L> *List<L>::addtoback(L data) {
[...]
}
template <class L>
// Return a pointer to a copy of the first item in the list.
Node<L> *List<L>::getfirst() {
[...]
}
template <class L>
// Return a list of all but the first element of the original.
List<L> List<L>::getrest() {
[...]
}
template <class L>
// Print out the data in each node separated by a space.
void List<L>::show() {
Node<L> *current_node = first;
while (current_node != NULL) {
cout << current_node->data << " ";
current_node = current_node->next;
}
cout << endl;
}
template <class L>
// Returns a reversed version of toReverse
List<L> List<L>::reverse(List toReverse) {
[...]
}