Linker error in templated vector class

This is a discussion on Linker error in templated vector class within the C++ Programming forums, part of the General Programming Boards category; Hi guys, I'm writing a rather basic templated vector class. I'm compiling in MSVC++ 6.0. I'm getting the "LNK2001: unresolved ...

  1. #1
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    Linker error in templated vector class

    Hi guys,

    I'm writing a rather basic templated vector class. I'm compiling in MSVC++ 6.0. I'm getting the "LNK2001: unresolved external symbol _WinMain@16" error when I attempt to compile. I've included my code below. I'm sure some of my functions may be a little off, but I can't correct that until I can run the debugger, and of course, test cases. Let me know if you see anything stupid, or otherwise, thanks!


    my_vec.h:

    Code:
    #include<iostream>
    #include<iomanip>
    
    using namespace std;
    
    template<class T>
    class my_vec{
    //class requires that the operator = is defined for T.
    
    private:
    		T *array;          // pointer to the vector
    		int back;          // index of last element.  -1 if vector empty
    		int max_index;     // last available index.  -1 if vector invalid
    		void increase()    // increases the size of the vector if needed.
            { if(back == -1) { back = 0; max_index = 32; } else max_index = max_index * 2 - 1; } 
    public:
    		// Misc useful
    	    typedef T* iterator;
    		void printMe();
    
    		// Constructors
    		my_vec();  // back=max_index=-1.  array=Null.
    		my_vec(int); // put in "int" elements, uninitialized, back=-1
    
    		// Destructor
    		~my_vec();  // free the array
    
    		// General purpose  
    		int size() // return current size
    		{ return(back+1); } 
    		
            iterator begin() // return iterator to start of array
            { iterator i = array; return i; } 
    		
            iterator end()   // return iterator to 1 past last elem of array.
            { iterator i = &(array[back + 1]); return i; }
    
    		// add and remove
    		void push_back(T);   // add to end of array
    		void pop_back();     // remove value at end of array (note: is void !!!)
    		void erase(iterator);
    		void insert(iterator,T);  // insert element into location pointed to
    		                          // by the iterator, shifting rest forward.
    
    		// operator overload for indexing, both rhs and lhs!
    		T& operator[](int i)
            { return array[i]; }
    };
    
    template <class T>
    void my_vec<T>::printMe()
    {
    	cout << "* STRUCT " << endl;
    	cout << "  max_index=" << max_index << endl;
    	cout << "  back=" << back << endl;
    	if(max_index!=-1)
    		for(int i=0;i<=back;i++)
    		{
    			cout << setw(8) << array[i] << "  ";
    			if( (i%8) ==7 )
    				cout<< endl; 
    		}
    	else
    		cout << "BLANK"<<endl;
    	
    	cout << endl;
        return;
    };
    
    template <class T>
    my_vec<T>::my_vec()
    {
        back = max_index = -1;
        array = NULL;
    }
    
    template <class T>
    my_vec<T>::my_vec(int n)
    {
        array = new T[n];
        back = n - 1;
        if (n <= 32)
        {        
            max_index = 31;
        }
        else
        {
            max_index = n * 2;
        }
    
    }
    
    template <class T>
    my_vec<T>::~my_vec()
    {
        while (back + 1 > 0)
            pop_back();
    }
    
    template <class T>
    void my_vec<T>::push_back(T t)
    {
        if (back == max_index) increase();
        back++;
        T* temp = new T[back + 1];
        temp[back] = t;
        for (int i = 0; i < back; i++) temp[i] = array[i];
        delete [] array;
        array = temp;
    }
    
    template <class T>
    void my_vec<T>::pop_back()
    {
        if (back != -1)
        {
            back--;
            T* temp = new T[back + 1];
            for (int i = 0; i < back + 1; i++) temp[i] = array[i];
            delete [] array;
            array = temp;
        }
    }
    
    template <class T>
    void my_vec<T>::erase(iterator i)
    {
        if (back != -1)
        {
            back--;
            T* temp = new T[back + 1];
            bool found = false;
            for (int j = 0; j < back + 1; j++)
            {
                if (i != &(array[j]) && !found) temp[j] = array[j];
                else if (found) temp[j] = array[j + 1];
                else found = true;
            }
            delete [] array;
            array = temp;
        }
            
    }
    
    template <class T>
    void my_vec<T>::insert(iterator i, T t)
    {
        if (back == max_index) increase();
        back++;
        T* temp = new T[back + 1];
        bool found = false;
        for (int j = 0; j < back + 1; j++)
        {
            if (i != &(array[j + 1]) && !found) temp[j] = array[j];
            else if (found) temp[j] = array[j - 1];
            else { found = true; temp[j] = t; }
        }
        
        delete [] array;
        array = temp;
    }

    main1.cpp

    Code:
    #include<iostream>
    #include<iomanip>
    #include"my_vec.h"
    
    using namespace std;
    
    int main(int argc, char * argv[]) 
    {
    	my_vec<int> vec;
    	my_vec<int>::iterator i;
    	vec.printMe();
    	vec.push_back(1);
    	cout << "1" << endl;
        vec.push_back(2);
    	cout << "2" << endl;
        vec.push_back(3);
    	cout << "3" << endl;
        vec.push_back(4);
    	cout << "4" << endl;
        vec.printMe();
    	
        vec[0]=vec[3];
    	vec.printMe();
    	i=vec.end()-2;
    	vec.insert(i,9);
    	vec.printMe();
    	i=vec.begin();
    	vec.erase(i);
    	vec.printMe();
    	cout << "All done!"<<endl;
    
        return 0;
    }

  2. #2
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    i'm not sure, but are you trying to build console or winapi? check your project.

  3. #3
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    I am building a Win32 Console App, so as to mimic the Unix environment as much as possible. After developing on Windows, I transport to Unix, and recompile on g++. This has been my approach forever, and has never caused problems in the past, even with much more complex things. In fact, this program compiles on g++, but I have some bugs to work out, that I would MUCH prefer to do with the debugger in MSVC.

  4. #4
    geek SilentStrike's Avatar
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    Ever try the debugger in KDevelop? It offers the same basic functionality (set breakpoints from the IDE, jump into, jump out of, step, etc).

    No winmain means you set up a windows project and are using conventional int main, instead of winmain or whatever. Make a console project from MSVC, and it should all work out.

  5. #5
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    that's what i was referring to, what type of main you were using, if it matched your project. as silentstrike stated.

  6. #6
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    Ok, I'll give it a try...!

    We'll see what happens. Thanks

  7. #7
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    Haha, yeah. Believe it or not, I had accidently created a regular Win App, nota console app. Thanks for your input guys.

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