diff --git a/src/vector.c b/src/vector.c
index 05323bf5..d3ee94fc 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -28,7 +28,8 @@ make_vector__ (long k)
 {
   SCM v = alloc (k);
   SCM x = make_cell__ (TVECTOR, k, v);
-  for (long i = 0; i < k; i++)
+  long i;
+  for (i = 0; i < k; i = i + 1)
     g_cells[v + i] = g_cells[vector_entry (cell_unspecified)];
   return x;
 }
@@ -98,7 +99,8 @@ list_to_vector (SCM x)
   SCM p = VECTOR (v);
   while (x != cell_nil)
     {
-      g_cells[p++] = g_cells[vector_entry (car (x))];
+      g_cells[p] = g_cells[vector_entry (car (x))];
+      p = p + 1;
       x = cdr (x);
     }
   return v;
@@ -108,7 +110,8 @@ SCM
 vector_to_list (SCM v)
 {
   SCM x = cell_nil;
-  for (long i = LENGTH (v); i; i--)
+  long i;
+  for (i = LENGTH (v); i; i = i - 1)
     {
       SCM e = VECTOR (v) + i - 1;
       if (TYPE (e) == TREF)