CC=gcc
CFLAGS=-g3 -Wall

PROGRAMS=calc

all: $(PROGRAMS)

test: all
	echo '*+ 1 2 + 3 4 * 123 456' | ./calc

calc: calc.o expr.o
	$(CC) $(CFLAGS) -o $@ $^

calc.o: calc.c expr.h
expr.o: expr.c expr.h

clean:
	$(RM) *.o $(PROGRAMS)