--- main.c.org	2015-10-15 10:00:00.000000000 +0300
+++ main.c	2015-10-19 00:46:37.500000000 +0300
@@ -417,12 +417,28 @@
 *  the branch-and-cut algorithm. */
 
 void cb_func(glp_tree *T, void *info)
-{     xassert(info == info);
+{     static int j, k;
+      if (k == 0)
+         k = glp_get_num_cols(P);
+      xassert(info == info);
       switch (glp_ios_reason(T))
       {  case GLP_IROWGEN:
             /* generate one violated subtour elimination constraint */
             gen_subt(T);
             break;
+         case GLP_IHEUR:
+            for (j = 1; j <= k; j++)
+            {  if (glp_get_col_kind(P, j) == GLP_BV)
+               {  glp_set_col_kind(P, j, GLP_CV);
+                  break;
+               }
+            }
+            break;
+         case GLP_ICUTGEN:
+            if (j > 0 && j <= glp_get_num_cols(P))
+               glp_set_col_kind(P, j, GLP_BV);
+            j = 0;
+            break;
       }
       return;
 }