1 files changed, 96 insertions, 0 deletions
diff --git a/src/johnson/stack.c b/src/johnson/stack.c
new file mode 100644
index 0000000..daee722
--- /dev/null
+++ b/src/johnson/stack.c
@@ -0,0 +1,96 @@
+/**
+ *  This program is free software: you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License as
+ *  published by the Free Software Foundation, either version 3 of the
+ *  License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  (c) Vincenzo Nicosia 2009-2017 -- <v.nicosia@qmul.ac.uk>
+ * 
+ *  This file is part of NetBunch, a package for complex network
+ *  analysis and modelling. For more information please visit:
+ *
+ *             http://www.complex-networks.net/
+ *
+ *  If you use this software, please add a reference to 
+ *
+ *               V. Latora, V. Nicosia, G. Russo             
+ *   "Complex Networks: Principles, Methods and Applications"
+ *              Cambridge University Press (2017) 
+ *                ISBN: 9781107103184
+ *
+ ***********************************************************************
+ *
+ *  Implementation of a stack data structure (for unsigned integers)
+ *
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "stack.h"
+
+void stack_create(my_stack_t *s){
+  
+  s->size = 10;
+  s->head = -1;
+  s->v = malloc(s->size * sizeof(int)); 
+  
+}
+
+void stack_push(my_stack_t *s, unsigned int n){
+  
+  if (s->head == s->size - 1){
+    s->size += 10;
+    s->v = realloc(s->v, s->size * sizeof(unsigned int));
+    if (!s->v){
+      fprintf(stderr, "Unable to allocate more memory in stack.c:stack_push... Exiting!\n");
+      exit(17);
+    }
+  }
+  
+  s->head++;
+  s->v[s->head] = n;
+}
+
+int stack_pop(my_stack_t *s, unsigned int *res){
+
+  if (!stack_empty(s)){
+    *res = s->v[s->head];
+    s->head--;
+    return 0;
+  }
+  else{
+    return -1;
+  }
+  
+}
+
+int stack_empty(my_stack_t *s){
+
+  return (s->head < 0 ? 1 : 0);
+}
+
+
+void stack_dump(my_stack_t *s, FILE *fileout){
+  
+  int i;
+
+  for(i=s->head; i>=0; i--){
+    fprintf(fileout, "%d ", s->v[i]);
+  }
+  fprintf(fileout, "\n");
+}
+
+
+int stack_size(my_stack_t *s){
+  return s->head + 1;
+}