Fix segfault caused in 'dfs.zc'

3 files changed, 11 insertions, 2 deletions

diff --git a/docs/std/vec.md b/docs/std/vec.md
index 7bc7c05..525e179 100644
--- a/docs/std/vec.md
+++ b/docs/std/vec.md
@@ -63,6 +63,7 @@ struct Vec<T> {
 | Method | Signature | Description |
 | :--- | :--- | :--- |
 | **get** | `get(self, idx: usize) -> T` | Returns a copy of the element at `idx`. Panics if out of bounds. |
+| **get_ref** | `get_ref(self, idx: usize) -> T*` | Returns a pointer to the element at `idx`. Panics if out of bounds. Useful for avoiding copies. |
 | **set** | `set(self, idx: usize, item: T)` | Overwrites the element at `idx`. Panics if out of bounds. |
 | **first** | `first(self) -> T` | Returns a copy of the first element. Panics if empty. |
 | **last** | `last(self) -> T` | Returns a copy of the last element. Panics if empty. |
diff --git a/examples/algorithms/dfs.zc b/examples/algorithms/dfs.zc
index 2d4670c..e51acfa 100644
--- a/examples/algorithms/dfs.zc
+++ b/examples/algorithms/dfs.zc
@@ -32,7 +32,7 @@ impl Graph {
         visited[vertex] = true;
         order.push(vertex);
 
-        let neighbors = self.adj_list.data[vertex];
+        let neighbors = self.adj_list.get_ref(vertex);
         let neighbor_count = (int)neighbors.len;
         for i in 0..neighbor_count {
             let neighbor = neighbors.data[i];
@@ -83,7 +83,7 @@ impl Graph {
             visited.data[vertex] = true;
             order.push(vertex);
 
-            let neighbors = self.adj_list.data[vertex];
+            let neighbors = self.adj_list.get_ref(vertex);
             let i = (int)neighbors.len - 1;
             while i >= 0 {
                 let neighbor = neighbors.data[i];
diff --git a/std/vec.zc b/std/vec.zc
index 16f23a7..59142d7 100644
--- a/std/vec.zc
+++ b/std/vec.zc
@@ -190,6 +190,14 @@ impl Vec<T> {
         return self.data[idx];
     }
 
+    fn get_ref(self, idx: usize) -> T* {
+        if (idx >= self.len) {
+            !"Panic: Index out of bounds";
+            exit(1);
+        }
+        return &self.data[idx];
+    }
+
     fn last(self) -> T {
         if (self.len == 0) {
             !"Panic: last called on empty Vec";