diff --git a/graph.c b/graph.c
index f66bd02..e849805 100644
--- a/graph.c
+++ b/graph.c
@@ -24,7 +24,7 @@ void vertex_free(void *data) {
     free(vertex);
 }
 
-Graph *graph_create() {
+Graph *graph_create(void) {
 	Graph *graph = malloc(sizeof(Graph));
 	graph->vertices = list_create(vertex_free);
 	graph->count = 0;
diff --git a/graph.h b/graph.h
index eaab1f1..879cfe1 100644
--- a/graph.h
+++ b/graph.h
@@ -23,7 +23,7 @@ typedef struct Graph {
 	int count;
 } Graph;
 
-Graph *graph_create();
+Graph *graph_create(void);
 Vertex *vertex_create(void *data);
 Edge *edge_create(Vertex *vertex, double weight);