CC = gcc
CFLAGS = -Wall -Wextra -std=c99
dIRS = a1 du1 du2 du3 du4 du5 a3
all: 
	@for %%d in ($(dIRS)) do \
		$(CC) $(CFLAGS) %%d\program.c -o %%d\program.exe
clean:
	@for %%d in ($(dIRS)) do \
		if exist %%d\program.exe del %%d\program.exe
build-%:
	$(CC) $(CFLAGS) $*/program.c -o $*/program.exe