Undefined referece to class constructor - c++

Question

I'm getting the following error:
> /tmp/ccYbdvB8.o: In function `main':
> /home/caleb/Documents/dev/cs438/tote2/mp2/manager.cpp:5: undefined
> reference to `TCPConnection::TCPConnection(char const*, char const*)'
> collect2: error: ld returned 1 exit status make: *** [manager] Error 1
I've included the header to the class I'm trying to initialize.. so I'm thinking maybe it's my makefile? I'm pretty new to writing custom makefiles...
cpp:
#include "tcpcon.h"
const string TCPConnection::Client = "client";
const string TCPConnection::Server = "server";
TCPConnection::TCPConnection(const char* t, const char* p) : target(t), port(p)
{ }
h:
class TCPConnection{
public:
TCPConnection(const char *target, const char *port);
main:
#include "tcpcon.h"
int main()
{
TCPConnection *TCPCon = new TCPConnection("localhost", "7777");
cout << "Hi\n";
return 0;
}
makefile:
CC=g++
CCOPTS=-Wall -Wextra -g
OBJS = tcpcon.o
TARGETS = manager
.PHONY: all clean
$(TARGET) : $(OBJS)
$(CC) -o $# $^ $(CFLAGS) $(LIBS)
all: $(OBJS) $(TARGETS)
clean:
rm -f $(TARGETS) $(OBJS)
%: %.cpp
$(CC) $(CCOPTS) -o $# $<

Answer 1

It turns out that the issue may have been related to a couple of things:
Use of $(TARGET) instead of $(TARGETS) in one place
Did not include the main file (manager.cpp) to the OBJS list
My updated makefile is below:
CC=g++
CCOPTS=-Wall -Wextra -g
OBJS = manager.o tcpcon.o
TARGETS = manager
.PHONY: all clean
$(TARGETS) : $(OBJS)
$(CC) -o $# $^ $(CFLAGS) $(LIBS)
all: $(TARGETS) $(OBJS)
clean:
rm -f $(TARGETS) $(OBJS)
%: %.cpp
$(CC) $(CCOPTS) -o $# $<