diff --git a/Makefile b/Makefile
index ac6b05b..6e1816b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,5 +1,5 @@
 subnetcalc: subnetcalc.c
-	gcc subnetcalc.c -lm -o subnetcalc
+	gcc -Wall -pedantic subnetcalc.c -lm -o subnetcalc
 
 clean: subnetcalc
 	rm subnetcalc
diff --git a/subnetcalc.c b/subnetcalc.c
index 838157a..68135c9 100644
--- a/subnetcalc.c
+++ b/subnetcalc.c
@@ -6,13 +6,13 @@
 #include <stdio.h>
 #include <math.h>
 
-main()
+int main(void)
 {
     int net;
     double hosts;
     double addr;
     printf("Enter netmask in slash-notation without the slash: ");
-    scanf("%d", &net);
+    scanf("%2d", &net);
 
     if (net >= 0 && net <= 32) // Sanity check the user input
     {