fix(codes/c): Fix unknown behavior when size is 0 or arr is a null pointer (#288)

Co-authored-by: Yudong Jin <krahets@163.com>

codes/c/include/print_util.h

@@ -27,17 +27,21 @@ extern "C" {
  */
 static void printArray(int arr[], int size) {
     printf("[");
-    for (int i = 0; i < size - 1; i++) {
-        if (arr[i] != NIL) {
-            printf("%d, ", arr[i]);
-        } else {
-            printf("NULL, ");
-        }
-    }
-    if (arr[size - 1] != NIL) {
-        printf("%d]\n", arr[size - 1]);
+    if (arr != NULL && size != 0) {
+      for (int i = 0; i < size - 1; i++) {
+          if (arr[i] != NIL) {
+              printf("%d, ", arr[i]);
+          } else {
+              printf("NULL, ");
+          }
+      }
+      if (arr[size - 1] != NIL) {
+          printf("%d]\n", arr[size - 1]);
+      } else {
+          printf("NULL]\n");
+      }
     } else {
-        printf("NULL]\n");
+      printf("]");
     }
 }