Avoid all other warnings

ColoredSquare.c

@@ -71,13 +71,19 @@ ColoredSquare* ColoredSquare_new (double a, int color)
 {
   static ColoredSquare_interface vtable =
     {
-      (void* (*) (void *)) ColoredSquare_clone,
-      (void (*) (void *)) Square_destroy,
-      (const char* (*) (Figure *)) ColoredSquare_type,
-      (void (*) (Figure *)) ColoredSquare_draw,
-      (double (*) (Figure *)) Square_area,
-      Square_resize,
-      Square_diag_length,
+      {
+        {
+          {
+            (void* (*) (void *)) ColoredSquare_clone,
+            (void (*) (void *)) Square_destroy
+          },
+          (const char* (*) (Figure *)) ColoredSquare_type,
+          (void (*) (Figure *)) ColoredSquare_draw,
+          (double (*) (Figure *)) Square_area
+        },
+        Square_resize,
+        Square_diag_length
+      },
       ColoredSquare_set_color
     };
   ColoredSquare *square = malloc (sizeof (*square));

Square.c

@@ -102,11 +102,15 @@ Square* Square_new (double a)
 {
   static Square_interface vtable =
     {
-      (void* (*) (void *)) Square_clone,
-      (void (*) (void *)) Square_destroy,
-      (const char* (*) (Figure *)) Square_type,
-      (void (*) (Figure *)) Square_draw,
-      (double (*) (Figure *)) Square_area,
+      {
+        {
+          (void* (*) (void *)) Square_clone,
+          (void (*) (void *)) Square_destroy
+        },
+        (const char* (*) (Figure *)) Square_type,
+        (void (*) (Figure *)) Square_draw,
+        (double (*) (Figure *)) Square_area
+      },
       Square_resize,
       Square_diag_length
     };

main.c

@@ -3,7 +3,7 @@
 
 #include "ColoredSquare.h"
 
-int main (int argc, char *argv[])
+int main (void)
 {
   unsigned long i = 0;
   Figure *fig[3];