# Any line that starts with a sharp is a comment and is ignored
# by Make.

# These lines set variables that control make's default rules.
# We STRONGLY recommend putting "-g3 -Wall" in your CFLAGS.
CC=gcc
CFLAGS=-g3 -Wall

# The next line is a dependency line.
# It says that if somebody types "make all"
# make must first make "hello-world".
# By default the left-hand-side of the first dependency is what you
# get if you just type "make" with no arguments.
all: hello-world

# How do we make hello-world?
# The dependency line says you need to first make hello-world.o
# and hello-library.o
hello-world: hello-world.o hello-library.o
	# Subsequent lines starting with a TAB character give
	# commands to execute.
	# This command uses make built-in variables to avoid
	# retyping (and getting things wrong):
	#  $@ = target hello-world
	#  $^ = dependencies hello-world.o and hello-library.o
	$(CC) $(CFLAGS) -o $@ $^
	# You can put whatever commands you want.
	echo "I just built hello-world!  Hooray!"

# Here we are saying that hello-world.o and hello-library.o
#  should be rebuilt whenever their corresponding source file
#  or hello-library.h changes.
# There are no commands attached to these dependency lines, so
#  make will have to figure out how to do that somewhere else
#  (probably from the builtin .c -> .o rule).
hello-world.o: hello-world.c hello-library.h
hello-library.o: hello-library.c hello-library.h

# Command lines can do more than just build things.  For example,
# "make test" will rebuild hello-world (if necessary) and then run it.
test: hello-world
	./hello-world

# This lets you type "make clean" and get rid of anything you can
# rebuild.  The $(RM) variable is predefined to "rm -f"
clean:
	$(RM) hello-world *.o