在很多C/C++工程中原始檔放到一個目錄下面，標頭檔案放在另一個目錄下面，這樣生成的目標檔案（.o檔案）直接放在原始檔相同的資料夾下。但是對於多個目錄中都存在原始檔的情況下，無論將目標檔案放在一個目錄下還是放在和對應原始檔相同的目錄下都不像所有原始檔在一個目錄下那樣簡單。下面取makefile中的一部分來說明，該makefile是將目標檔案放在和對應的原始檔相同的目錄下。

CXXFLAGS := -std=c++11 -g -Wall

CXX := g++
SRC1 =  $(wildcard ./*.cpp) 
SRC2 = $(wildcard ./table/*.cpp) 
SRC3 = $(wildcard ./checker/*.cpp)
OBJ1 = $(patsubst %.cpp,%.o,$(SRC1))
OBJ2 = $(patsubst %.cpp,%.o,$(SRC2))
OBJ3 = $(patsubst %.cpp,%.o,$(SRC3))
src2 = ./table/
src3 = ./checker/
TARGETS := main
$(TARGETS) : $(OBJ1) $(OBJ2) $(OBJ3)
@$(CXX) $^ $(LIB) -o

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@echo "prepare successfully!"
%.o:$(src2)/%.cpp 
@echo "prepare Compile "
@$(CXX) -c $< $(CXXFLAGS) $(INCLUDE) -o [email protected]
@echo "Compiled "$<" successfully!"
%.o:$(src3)/%.cpp 
@echo "prepare Compile "
@$(CXX) -c $< $(CXXFLAGS) $(INCLUDE) -o [email protected]
@echo "Compiled "$<" successfully!"
%.o:%.cpp 
@echo "prepare Compile "
@$(CXX) -c $< $(CXXFLAGS) $(INCLUDE) -o

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@echo "Compiled "$<" successfully!"


.PHONY : clean
clean:
@-rm $(TARGETS) $(OBJ1) $(OBJ2) $(OBJ3) -f
@echo "Cleanup complete!"