Can not find header in Automake

Question

I was learning GNU autotools (autoconf, automake) with this helloworld example. My project tree is like this:

|-- aclocal.m4
    |-- AUTHORS
    |-- autom4te.cache
    |   |-- output.0
    |   |-- output.1
    |   |-- requests
    |   |-- traces.0
    |   `-- traces.1
    |-- autoscan.log
    |-- ChangeLog
    |-- config.h.in
    |-- configure
    |-- configure.ac
    |-- COPYING
    |-- depcomp
    |-- include
    |   |-- hello.hpp
    |   `-- world.hpp
    |-- INSTALL
    |-- install-sh
    |-- lib
    |   |-- hello.cpp
    |   |-- Makefile.am
    |   |-- Makefile.in
    |   `-- world.cpp
    |-- Makefile.am
    |-- Makefile.in
    |-- missing
    |-- NEWS
    |-- README
    `-- src
        |-- main.cpp
        |-- Makefile.am
        `-- Makefile.in

I build like this:

$autoreconf -vfi 
$./configure
$make 

... and get a compilation failure:

Making all in src
make[2]: Entering directory `/home/suddin/package_directory/src'
g++ -DHAVE_CONFIG_H -I. -I..     -g -O2 -MT main.o -MD -MP -MF .deps/main.Tpo -c -o main.o main.cpp
main.cpp:7:21: fatal error: hello.hpp: No such file or directory
 #include "hello.hpp"
                     ^

I was able to build successfully by changing my #include directives to these:

#include "../include/hello.hpp"
#include "../include/world.hpp"

, but I would prefer to keep them as they are:

#include "hello.hpp"
#include "world.hpp"

My src/Makefile.am file contains the following line; why does it not resolve the issue?

helloWorld_CXXFLAGS=-I../include      ##Add path to header file

For context, here are all my Makefile.am files:

===== src/Makefile.am ======================

bin_PROGRAMS=helloworld
helloworld_SOURCES=main.cpp
helloworld_CXXFLAGS= -I../include ## add path to headerfiles
helloworld_LDADD=../lib/libhw.a ## link with static library

===== lib/Makefile.am =======================

noinst_LIBRARIES=libhw.a ## static library which is not to be installed
libhw_a_SOURCES=hello.cpp hello.hpp world.cpp world.hpp
libhw_a_CXXFLAGS=-I../include ## add path to headerfiles

===== Makefile.am (top level) =================

 SUBDIRS=lib src ## processing subdirs in given order

Answer 1

Typing mistake, "helloWorld_CXXFLAGS " should be "helloworld_CXXFLAGS".