Implement pre-increment / pre-decrement
diff --git a/libacc/tests/data/inc.c b/libacc/tests/data/inc.c
index eda3659..14c09d1 100644
--- a/libacc/tests/data/inc.c
+++ b/libacc/tests/data/inc.c
@@ -6,5 +6,9 @@
     printf("%d\n", a++);
     printf("%d\n", a--);
     printf("%d\n", a--);
+    printf("%d\n", ++a);
+    printf("%d\n", ++a);
+    printf("%d\n", --a);
+    printf("%d\n", --a);
     return a;
 }
diff --git a/libacc/tests/test.py b/libacc/tests/test.py
index 5f9a71e..0249695 100644
--- a/libacc/tests/test.py
+++ b/libacc/tests/test.py
@@ -293,6 +293,10 @@
 1
 2
 1
+1
+2
+1
+0
 result: 0
 ""","""""")