Shall I prefer constants over defines?

Constants should be preferred over defines. There are several advantages:

• Type safety. While C is a weakly typed languaged, using a define loses all of the type safety, which will allow the compiler to pick up problems for you.

• Ease of debugging. You can change the value of constants through the debugger, while defines are automatically changed in the code by the pre-processor to the actual value, meaning that if you want to change the value for test/debugging purposes, you need to re-compile.