如何为带有.h文件的几个.cpp文件和不带有.h的main.cpp创建一个makefile

Question

I have:

main.cpp 
distance.cpp
distance.h
adjacencyList.cpp
adjacencyList.h

Here is my makefile:

all: distance main adjacencyList
    g++ distance.o main.o adjacencyList.o

main.o: main.cpp
    g++ main.cpp -lstdc++

adjacencyList.o: adjacencyList.cpp
    g++ adjacencyList.cpp -lstdc++

distance.o: distance.cpp
    g++ distance.cpp -lstdc++

clean:
    rm -rf *.o all

I am getting this error. So I'm pretty sure I'm doing something wrong with main because it is not a class like the other two and does not have a .h file.

Update:

After trying Ben Voigt's solution I am getting 1 error:

Answer 1

Your rules to create object files are missing the -c option, for "compile only". So they are trying to link, and failing because there is no main() .

Then, your all target names an executable for each of the compilation units. Again, that's wrong because they don't all have main() . You should have only one executable. all should also be configured as a phony target, because it doesn't build an actual file named all .

All your rules are failing to control the name of the output file.

All your rules are failing to pass flags.

Your rules are missing dependencies on the headers, so editing headers won't cause the right files to be recompiled.

Really, you should get rid of the compile and link rules and let make use its built-in ones. Focus on your build targets and dependencies.

Your end makefile should look something like this (of course, using spaces not tabs)

all : main

.PHONY : all clean

CC = g++
LD = g++

main : main.o adjacencyList.o distance.o

main.o: main.cpp adjacencyList.h distance.h

adjacencyList.o: adjacencyList.cpp adjacencyList.h

distance.o: distance.cpp distance.h

clean:
    rm -rf *.o main

Answer 2

Wild guess: it is possible you are missing a semi-colon somewhere before including adjacencyList.h. Check each header files and make sure each class definition is properly terminated with a semi-colon