无需构建:面向C++的Eclipse问题

我对Java和Eclipse有一些经验，但我是C++的新手，正在努力自学。如果这是一个简单的问题，或者已经被问到了（尽管我环顾四周了一段时间），我很抱歉。我使用的是Windows 8。

我正在尝试制作一个排序的链表（这相对不重要。）我得到了：

Info: Nothing to build for Working.

这是我的代码：

/*
*  SortedList class
*/
#include <string>
#include <fstream>
#include<iostream>
#include "SortedList.h"
using namespace std;
//the ListNode Structure
struct ListNode {
    string data;
    ListNode *next;
};
//the head of the linked list and the pointer nodes
ListNode head;
ListNode *prev, *current;
// insert a string into the list in alphabetical order
//now adds a string to the list and counts the size of the list
int Insert(string s){
//make the new node
ListNode temp;
temp.data = s;
//the node to traverse the list
prev = &head;
current = head.next;
int c = 0;
//traverse the list, then insert the string
while(current != NULL){
    prev = current;
    current = current->next;
    c++;
}
//insert temp into the list
temp.next = prev->next;
prev->next = &temp;
return c;
}
//Return the number of times a given string occurs in the list.
int Lookup(string s){
return 0;
}
//prints the elements of the list to ostream
void Print(ostream &output){
}
int main( int argc, char ** argv ) {
cout << Insert("a") << endl;
cout << Insert("b") << endl;
cout << Insert("d") << endl;
}

这是我的标题：

using namespace std;
#ifndef SORTEDLIST_H_
#define SORTEDLIST_H_
class SortedList {
  public:
    // constructor
    SortedList();
    // modifiers
    int Insert(string s);
    // other operations
    int Lookup(string s) const;
    void Print(ostream &output) const;
  private:
    struct ListNode {
       string data;
       ListNode *next;
    };
    // pointer to the first node of the list
    ListNode head;
    ListNode *prev, *current;
};
#endif /* SORTEDLIST_H_ */

如有任何帮助，我们将不胜感激。