Common C Error/Warning Messages ------------------------------- - "implicit declaration". This happens if you use a function without including the package that defines it. For example, if you call "cos" but forget to include , then the compiler will give you a warning that there is an implicit declaration of cos. - Don't put semicolons at the end of macro definitions. i had a tough time debugging this #define NUM_FISH 1024; It should have been #define NUM_FISH 1024