修改demo3

make_demo3/makefile → make_demo3/obj/makefile

 # 	@rm -rf $(BIN_DIR)
 
 
-VPATH:= main:module_1:module_2:module_3
-CFLAGS = -Wall -I include
+VPATH:= ../main:../module_1:../module_2:../module_3
+CFLAGS = -Wall -I ../include 
 BIN = myapp 
 OBJS = module_1.o module_2.o module_3.o main.o 
 BIN_DIR = bin
 # OBJS_DIR = obj
 
-$(BIN_DIR)/$(BIN): $(OBJS)
+../$(BIN_DIR)/$(BIN): $(OBJS)
 	$(CC) $(CFLAGS) $^ -o $@