diff --git a/datadec.c b/datadec.c
index b9e06bc9719e7f3930cbae8988fa0329bcbefa88..1c49203f142a664fa541ea30ad2d127a65550953 100644
--- a/datadec.c
+++ b/datadec.c
@@ -18,7 +18,9 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
+
 #include "struct.h"
 #include "lexer.h"
 #include "parser.h"
diff --git a/decs.c b/decs.c
index 5b695270a13e8433b51206e3741df43b2b3c2f46..93559271082b704b5e880ace5503db7f36657862 100644
--- a/decs.c
+++ b/decs.c
@@ -1,4 +1,6 @@
 #include <stdio.h>
+#include <stdlib.h>
+
 #include "struct.h"
 #include "decs.h"
 
diff --git a/lexer.c b/lexer.c
index d626da5dfc4e24b44fd177c4a34462e82429eb3f..229b402eafc62ccf8bbc07c73d76edb1dc13de6b 100644
--- a/lexer.c
+++ b/lexer.c
@@ -16,7 +16,10 @@
  
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <ctype.h>
+
 #include "struct.h"
 #include "lexer.h"
 
diff --git a/optimize.c b/optimize.c
index e3422d93a9d779576ce1ac730857d658b9438ff5..cbf3cd9c445090d17b2e40aa278dabb7079a080c 100644
--- a/optimize.c
+++ b/optimize.c
@@ -2,7 +2,9 @@
 
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
+
 #include "struct.h"
 #include "optimize.h"
 
diff --git a/struct.c b/struct.c
index 7ba069c8d005831622eff708d1817cbb3b8db993..a87ec543396a85bee393611b1709f02e1a744c0b 100644
--- a/struct.c
+++ b/struct.c
@@ -16,7 +16,10 @@
 
 
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
 #include <malloc.h>
+
 #include "struct.h"
 
 #define Puts(s)	fputs(s,stdout)