Vim autocmd not working with nnoremap

Question

I am trying to setup vim for compiling and runing c and c++ programs right inside the editor, but these don't seem to work:

autocmd! filetype *.c        nnoremap <leader>cc :!gcc -o %:p:r %<cr>
autocmd! filetype *.c        nnoremap <leader>cr :!gcc -o %:p:r %<cr>:!%:p:r<cr>
autocmd! filetype *.cpp *.cc nnoremap <leader>cc :!g++ -o %:p:r %<cr>
autocmd! filetype *.cpp *.cc nnoremap <leader>cr :!g++ -o %:p:r %<cr>:!%:p:r<cr>

Answer 1

The FileType autocommand uses the filetype not the filename to match against. You can instead use c and cpp. See :h FileType. However your problems do not end there:

• These are global mappings. There for open up a c file and the mappings change. Open up a cpp file and the mappings change no matter what buffer you are in. Use nnoremap <buffer> instead. See :h :map-local
• Using autocmd! without a group. autocmd! will remove all previously defined and add in the current autocommand. It would be best to create a group with augroup.
• Optionally you can use %< instead of %:r.
• You may also want to look into pushing this into an ftplugin or after/ftplugin variant. :h ftplugin and :h after-directory

All together:

augroup CBuild
  autocmd!
  autocmd filetype c   nnoremap <buffer> <leader>cc :!gcc -o %:p:r %<cr>
  autocmd filetype c   nnoremap <buffer> <leader>cr :!gcc -o %:p:r %<cr>:!%:p:r<cr>
  autocmd filetype cpp nnoremap <buffer> <leader>cc :!g++ -o %:p:r %<cr>
  autocmd filetype cpp nnoremap <buffer> <leader>cr :!g++ -o %:p:r %<cr>:!%:p:r<cr>
augroup END