If a number is evenly divisible by 2 with no remainder, then it is even. You can calculate the remainder with the modulo operator % like this num % 2 == 0 . If a number divided by 2 leaves a remainder of 1, then the number is odd. You can check for this using num % 2 == 1 .

Zero is an even number. In other words, its parity the quality of aninteger being even or odd is even. The simplest way to prove that zero iseven is to check that it fits the definition of "even": it is an integermultiple of 2, specifically 0 2.