Initial commit based on https://thegeekuday.wordpress.com/2012/11/14/calculator-progr...
-rw-r--r-- 25 .gitignore
-rw-r--r-- 146 Makefile
-rw-r--r-- 132 cal.l
-rw-r--r-- 606 cal.y
drwxr-xr-x - doc