Another thing i dont understand is why people hardcode 15. I would rather write (3 * 5) and let the compiler figure out that 3 * 5=15. This way i think it more

Another thing i dont understand is why people hardcode 15. I would rather write (3 * 5) and let the compiler figure out that 3 * 5=15. This way i think it more clearly states where the number 15 comes from. Any reason to write 15 over (3 * 5)?