diff --git a/autoload/neural/pre_process/cpp.vim b/autoload/neural/pre_process/cpp.vim
new file mode 100644
index 0000000..effd33e
--- /dev/null
+++ b/autoload/neural/pre_process/cpp.vim
@@ -0,0 +1,7 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: Pre-processing rules for C++ files.
+
+function! neural#pre_process#cpp#Process(buffer, input) abort
+    let a:input.prompt = 'Write C++ syntax. '
+    \   . a:input.prompt
+endfunction
diff --git a/test/vim/pre_process/test_cpp.vader b/test/vim/pre_process/test_cpp.vader
new file mode 100644
index 0000000..999b346
--- /dev/null
+++ b/test/vim/pre_process/test_cpp.vader
@@ -0,0 +1,12 @@
+Before:
+  let g:input = {'prompt': 'Do something.'}
+  call neural#config#Load()
+
+After:
+  unlet! g:input
+
+Given cpp(An empty C++ file):
+Execute(Basic C++ prompt editing should be done):
+  call neural#PreProcess(bufnr(''), g:input)
+
+  AssertEqual 'Write C++ syntax. Do something.', g:input.prompt