/in/foo.cc: In function 'int main()':
/in/foo.cc:23:12: error: expected ';' before 'r'
     printf r; 
            ^
/in/foo.cc:23:13: warning: statement is a reference, not call, to function 'printf' [-Waddress]
     printf r; 
             ^
/in/foo.cc:23:13: warning: statement has no effect [-Wunused-value]