Thread: Template compiler pains

Okay, so I've got a simple templated d-heap I'm trying to get compiled here. This is ironic because I'm trying to use this as part of my almost complete graph data structure and I can't even get something that should be simple to work! This is my first attempt at a template so maybe I'm missing something obvious. Anyways, here's some relevant bits of code:

Code:

#include <iostream>
#include <vector>
using namespace std;

template <class T,int dval>
class Heap
{
    private:
        vector<T> v;

    public:
        // constructor
        Heap(void);
        // heap methods
        bool empty(void) const;
        void insert (const T);
        T remove (void);
};

template <class T>
Heap<T>::Heap (void)
{
    //constructor stuff here
}
.
.
.

and here's some compilier errors:

Code:

In file included from graph.h:7,
                 from main.cpp:2:
heap.h:10: `Heap' is not a template type
heap.h:12: data member `v' cannot be a member template
heap.h:24: non-template type `Heap' used as a template
heap.h:25: ISO C++ forbids declaration of `Heap' with no type
heap.h:30: syntax error before `::' token
.
.
.

Thanks in advance for any direction!

Ooops, that was an addition. Anyways, same errors after I fixed that.

Originally Posted by JaWiB

Code:

template <class T, int dval>
Heap<T,dval>::Heap()
{
}

Yeah, that's what I have now but I still get the same errors.

Code:

#include <iostream>
#include <vector>
using namespace std;

template <class T,int dval>
class Heap
{
    private:
        vector<T> v;

    public:
        // constructor
        Heap(void);
        // heap methods
        bool empty(void) const;
        void insert (const T);
        T remove (void);
};

template <class T,int dval>
Heap<T,dval>::Heap (void)
{

Originally Posted by JaWiB

This compiles fine for me:

There's probably code you're not showing us that is causing the problem.

Yeah, I just tested it and it's not the heap code at all...that compiles fine. Is it that way I'm make-ing maybe? What code would be helpful to post?

Here's my make file:

Code:

#Makefile Template

TARGETS = main

CXX = g++
CXXFLAGS = -Wall -c
LDFLAGS = -Wall

all: $(TARGETS)

main: main.o edge.o vertex.o graph.o
        $(CXX) $(LDFLAGS) $^ -o $@

main.o: main.cpp graph.h
        $(CXX) $(CXXFLAGS) $<

graph.o: graph.cpp graph.h edge.h vertex.h heap.h
        $(CXX) $(CXXFLAGS) $<

edge.o: edge.cpp edge.h vertex.h
        $(CXX) $(CXXFLAGS) $<

vertex.o: vertex.cpp vertex.h
        $(CXX) $(CXXFLAGS) $<

# usage

# test: main.o class.o
#       $(CXX) $(LDFLAGS) $^ -o $@

# main.o: main.cpp class.h
#       $(CXX) $(CXXFLAGS) $<

clean:
        rm -f *.o $(TARGETS)

Here's an example of how I'm instansiating the heap:

Code:

// heap of nodes not in MST
Heap<Edge, 2> h;
// temp storage
Heap<Edge, 2> h2;

Edge is one of my own data types. The compile errors are completely limited to heap.h. But I copied heap.h into a file like this:

Code:

<heap.h code here>

int main ()
{
}

and it compiled fine.

This is so confounding. This is the last thing I need to get my graph working. Ideas anyone?

What are the errors if you put Heap<int, 2> h; inside your empty main? You won't get compile errors on a templated class unless you use it, which is probably why the empty main works.

Originally Posted by Daved

What are the errors if you put Heap<int, 2> h; inside your empty main? You won't get compile errors on a templated class unless you use it, which is probably why the empty main works.

That works fine. However, I figured out if I tried to do Heap<Edge, 2> h; that it fails with the exact same errors. So why is it failing? Do I have to do something special to my Edge class to make it useable in the template?

>> I figured out if I tried to do Heap<Edge, 2> h; that it fails with the exact same errors.
Post your Edge class if you're still not sure what the problem is.