Assertions

	never true or sometimes true / sometimes false. 

public static void mystery(Scanner input) {
	System.out.print("Enter a positive number: ");
	int num = input.nextInt();
	int z = num;
	int a = 0;
	<span class="assertionpoint">// Point A
	while (z > 0) {
		<span class="assertionpoint">// Point B
		if (a < z) {
			<span class="assertionpoint">// Point C
			a++;
		} else {
			z--;
		}
		num = z + 1;
		<span class="assertionpoint">// Point D
	}
	<span class="assertionpoint">// Point E
}

1) z > 0

2) num > 0

3) a < z