made copies of Makefile so that you can also use it in both bin and src

bin/Makefile

@@ -0,0 +1,33 @@
+# Universal makefile for single C++ program
+#
+# Use gcc flag -MMD (user) or -MD (user/system) to generate dependencies among source files.
+# Use make default rules for commonly used file-name suffixes and make variables names.
+#
+# % make [ a.out ]
+
+########## Variables ##########
+
+CXX = g++						# compiler
+CXXFLAGS = -std=c++20 -g -Wall -MMD -O0			# compiler flags
+MAKEFILE_NAME = ${firstword ${MAKEFILE_LIST}}		# makefile name
+
+SOURCES = $(wildcard ../src/*.cc)			# source files (*.cc)
+OBJECTS = ${SOURCES:.cc=.o}				# object files forming executable
+DEPENDS = ${OBJECTS:.o=.d}				# substitute ".o" with ".d"
+EXEC	= cc3k						# executable name
+
+########## Targets ##########
+
+.PHONY : clean						# not file names
+
+${EXEC} : ${OBJECTS}					# link step
+	${CXX} ${CXXFLAGS} -O0 $^ -o $@ -lncurses	# additional object files before $^
+
+${OBJECTS} : ${MAKEFILE_NAME}				# OPTIONAL : changes to this file => recompile
+
+# make implicitly generates rules to compile C++ files that generate .o files
+
+-include ${DEPENDS}					# include *.d files containing program dependences
+
+clean :							# remove files that can be regenerated
+	rm -f ${DEPENDS} ${OBJECTS} ${EXEC}

src/Makefile

@@ -0,0 +1,33 @@
+# Universal makefile for single C++ program
+#
+# Use gcc flag -MMD (user) or -MD (user/system) to generate dependencies among source files.
+# Use make default rules for commonly used file-name suffixes and make variables names.
+#
+# % make [ a.out ]
+
+########## Variables ##########
+
+CXX = g++						# compiler
+CXXFLAGS = -std=c++20 -g -Wall -MMD -O0			# compiler flags
+MAKEFILE_NAME = ${firstword ${MAKEFILE_LIST}}		# makefile name
+
+SOURCES = $(wildcard *.cc)				# source files (*.cc)
+OBJECTS = ${SOURCES:.cc=.o}				# object files forming executable
+DEPENDS = ${OBJECTS:.o=.d}				# substitute ".o" with ".d"
+EXEC	= ../bin/cc3k					# executable name
+
+########## Targets ##########
+
+.PHONY : clean						# not file names
+
+${EXEC} : ${OBJECTS}					# link step
+	${CXX} ${CXXFLAGS} -O0 $^ -o $@ -lncurses	# additional object files before $^
+
+${OBJECTS} : ${MAKEFILE_NAME}				# OPTIONAL : changes to this file => recompile
+
+# make implicitly generates rules to compile C++ files that generate .o files
+
+-include ${DEPENDS}					# include *.d files containing program dependences
+
+clean :							# remove files that can be regenerated
+	rm -f ${DEPENDS} ${OBJECTS} ${EXEC}