Add code for 11/10 exercise

Author: Margo

shell3x/GNUmakefile

@@ -0,0 +1,17 @@
+ALLPROG=sieve
+all: $(ALLPROG)
+O ?= -O2
+
+include ../common/rules.mk
+
+%: %.o $(BUILDSTAMP)
+	$(CC) $(LDFLAGS) -o $@ $<
+
+%.o: %.c $(BUILDSTAMP)
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(DEPCFLAGS) $(O) -o $@ -c $<
+
+clean:
+	rm -f $(ALLPROG) *.o
+	rm -rf $(DEPSDIR) *.dSYM
+
+.PHONY: all clean

shell3x/sieve.c

@@ -0,0 +1,31 @@
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <assert.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+// Fork a child, who reads from my stdout.
+// Then, read from standard in.
+// Output the first thing read to stderr
+// Then write everything after it to standard out, removing anything that
+// is a multiple of that first value.
+int main(int argc, char *argv[]) {
+	(void)argc;
+	(void)argv;
+
+	int val;
+
+	// Read first value and output to stderr
+	if (scanf("%d ", &val) != 1)
+		exit(1);
+	fprintf(stderr, "%d ", val);
+
+	// TODO: Read values from your standard input and write them to
+	// your standard output if they are not a multiple of val.
+}