Why can't Makefile find include directories - c++

Question

I can't seem to include a header in my test program using a Makefile.
I've attempted to try relative paths using -I with no luck. I'm new to Make and for some reason I am having a hard time understanding it's usage.
my code, test.cpp
#include <iostream>
#include <results/enumTest.h>
int main()
{
return 0;
}
and my Makefile:
CFLAGS = -Wall -g -Wextra -Wpedantic -std=gnu++11 -m64 -Iinclude
test: test.o
gcc $(CFLAGS) -I/.. -o test test.o
test.o: test.cpp
gcc $(CFLAGS) -I/.. -c test.cpp
my directory structure:
/testDir/
./results/enuMtest.h
./test/test.cpp
./test/Makefile
I would hope that I could compile and then run the test software using a Makefile. This is more or less a tutorial for me.

Answer 1

Your include path -I/.. is invalid. You're trying to access the parent directory of the root directory, which cannot exist. Change your Makefile to use relative paths instead with -I..
This will access the parent directory as intended:
CFLAGS = -Wall -g -Wextra -Wpedantic -std=gnu++11 -m64 -Iinclude
test: test.o
g++ $(CFLAGS) -I.. -o test test.o # Change here
test.o: test.cpp
g++ $(CFLAGS) -I.. -c test.cpp # ...and here
Note the removed slashes.
EDIT: As commented by #Lightness, you should include non-system headers with "header.h" rather than <header.h>. Additionally, since you are trying to compile a C++ program, it is recommended to use g++ instead of gcc (I've updated this in the snippet above).

Answer 2

There are several improvements possible.
You try to set the include path to the parent dir of / which is /.
You try to compile a c++ program using gcc but not g++
You don't need (it would still work) to set an include path, when linking. (test:
test.o)
Since there is no directory named include in the filetree you specified, you also don't need -Iinclude in the CFLAGS
Usually the C++ variant of CFLAGS is named CXXFLAGS, but I did not change it in the modified example below.
A corrected makefile would be:
CFLAGS = -Wall -g -Wextra -Wpedantic -std=gnu++11 -m64
test: test.o
g++ $(CFLAGS) -o test test.o
test.o: test.cpp
g++ $(CFLAGS) -I.. -c test.cpp
As an additional note:
#include "" instead of #include <> would also work. The difference is, that "" searches the included file relative from the location of the current source file, while <> uses the directories you specify using -I.
Find more details here