I had no problems using: gcc -o donut donut.c -lm You may also have errors in your version of donut.c, try copying the version from http://www.a1k0n.net/2006/0

I had no problems using: gcc -o donut donut.c -lm You may also have errors in your version of donut.c, try copying the version from http://www.a1k0n.net/2006/09/15/obfuscated-c-donut.html http://www.a1k0n.net/2006/09/15/obfuscated-c-donut.html