How can I improve this Makefile?

Question

I am working on creating a Makefile for my ProjectEuler solutions. I need to compile each solution into a separate binary for personal timing purposes. Is it possible to pass the name of the rule to the -o option to remove some repeated code?

CXX = g++
CXXFLAGS = -std=c++0x
INC = -Iinclude/ -I../tools/
binaries=01sum35\
 02evenfibs\
 03largestprimefactor\
 04largestpallyproduct\
 05smallestmultiple\
 06sumsquaredifference\
 07tenthousandfirstprime\
 08largestproductinseries\
 09specialpythagtriplet
all: $(binaries)
01sum35: 
 $(CXX) $(CXXFLAGS) 01sum35.cc $(INC) -o 01sum35 
02evenfibs:
 $(CXX) $(CXXFLAGS) 02evenfibs.cc $(INC) -o 02evenfibs
03largestprimefactor:
 $(CXX) $(CXXFLAGS) 03largestprimefactor.cc $(INC) -o 03largestprimefactor
04largestpallyproduct:
 $(CXX) $(CXXFLAGS) 04largestpallyproduct.cc ../tools/tools.cc $(INC) -o 04largestpallyproduct
05smallestmultiple:
 $(CXX) $(CXXFLAGS) 05smallestmultiple.cc $(INC) -o 05smallestmultiple
06sumsquaredifference:
 $(CXX) $(CXXFLAGS) 06sumsquaredifference.cc $(INC) -o 06sumsquaredifference
07tenthousandfirstprime:
 $(CXX) $(CXXFLAGS) 07tenthousandfirstprime.cc ../tools/tools.cc $(INC) -o 07tenthousandfirstprime
08largestproductinseries:
 $(CXX) $(CXXFLAGS) 08largestproductinseries.cc ../tools/tools.cc $(INC) -o 08largestproductinseries
09specialpythagtriplet:
 $(CXX) $(CXXFLAGS) 09specialpythagtriplet.cc $(INC) -o 09specialpythagtriplet
clean:
 rm -f $(binaries)

Answer 1

Yes:

CXX = g++
#
# Notice the +=. Use CPPFLAGS rather than INC for pre-processor rules.
#
CPPFLAGS += -Iinclude/ -I../tools/
CXXFLAGS += -std=c++0x
#
# Move the backslash
# This will stop it looking like a directory at first glance.
binaries=01sum35 \
 02evenfibs \
 03largestprimefactor \
 04largestpallyproduct \
 05smallestmultiple \
 06sumsquaredifference \
 07tenthousandfirstprime \
 08largestproductinseries \
 09specialpythagtriplet
all: $(binaries)
clean:
 rm -f $(binaries)
# Default rules and dependencies works for all the targets
# except the following which need one more file (dependency)
04largestpallyproduct: 04largestpallyproduct.cc ../tools/tools.cc
07tenthousandfirstprime: 07tenthousandfirstprime.cc ../tools/tools.cc
08largestproductinseries: 08largestproductinseries.cc ../tools/tools.cc

Answer 2

A few extra things that add to the post from @LokiAstari
In the listing below:

1. Add some warnings, -Wall as a minimum
2. Use VPATH to find the source files for the tools
3. Mark targets that are not created as 'phony'. This stops make from doing some searches and prevents the makefile failing if a file called all or clean ever exists.
4. Added some cleanup files
5. By making the binaries that depend on the tools depend on the tools.o object file not the source file, you avoid recompiling tools.cc for every binary. Because we have a VPATH defined, the path to tools.cc need not be specified.

Here's the simplified file:

CXX = g++
CPPFLAGS += -Iinclude/ -I../tools/
CXXFLAGS += -std=c++0x -Wall (1)
VPATH = ../tools (2)
binaries = a b c
.PHONY : all (3)
all: $(binaries)
.PHONY : clean (3)
clean:
 rm -f $(binaries) *.o *~ (4)
b: b.c tools.o (5)
c: c.c tools.o (5)

• Loki Astari: The new thing I learned today is VPATH. I have used make a lot and its the first time I have heard this.
• William Morris: @LokiAstari I've learnt many things from your answers to the many C++ questions, so I am glad it is now not an entirely one-way street :-)

Answer 3

You could use suffix rules (the .c.o part below) to tell make how to compile a c file. Then you can just tell the dependencies for each target.

CXX = g++
CXXFLAGS = -std=c++0x
INC = -Iinclude/ -I../tools/
binaries=01sum35\
 02evenfibs\
 03largestprimefactor\
 04largestpallyproduct\
 05smallestmultiple\
 06sumsquaredifference\
 07tenthousandfirstprime\
 08largestproductinseries\
 09specialpythagtriplet
all: $(binaries)
01sum35: 01sum35.cc
02evenfibs: 02evenfibs.cc
03largestprimefactor: 03largestprimefactor.cc 
04largestpallyproduct: 04largestpallyproduct.cc ../tools/tools.cc
05smallestmultiple: 05smallestmultiple.cc
06sumsquaredifference: 06sumsquaredifference.cc
07tenthousandfirstprime: 07tenthousandfirstprime.cc ../tools/tools.cc
08largestproductinseries: 08largestproductinseries.cc ../tools/tools.cc
09specialpythagtriplet: 09specialpythagtriplet.cc 
.cc.o:
 $(CXX) $(CXXFLAGS) $< $(INC) -o $@
clean:
 rm -f $(binaries)