Program Logic and Indefinite Loops - Building Java Programs: A Back to Basics Approach - page 368

prev = next;
next = console.nextInt();
// Point D

}
// Point E
return count;

}

Categorize each assertion at each point with ALWAYS, NEVER, or SOMETIMES:

next == 0 prev == 0 next == prev

Point A
Point B
Point C
Point D
Point E

Exercises

1. Write a method called showTwos that shows the factors of 2 in a given integer. For example, consider the following
calls:

showTwos(7);
showTwos(18);
showTwos(68);
showTwos(120);

These calls should produce the following output:

7 = 7
18 = 2 * 9
68 = 2 * 2 * 17
120 = 2 * 2 * 2 * 15

2. Write a method called gcd that accepts two integers as parameters and returns the greatest common divisor (GCD)
of the two numbers. The GCD of two integers a and b is the largest integer that is a factor of both a and b .

One efficient way to compute the GCD of two numbers is to use Euclid's algorithm, which states the following:

GCD ( a , b ) GCD ( b , a % b )

GCD ( a , 0) Absolute value of a

3. Write a method called toBinary that accepts an integer as a parameter and returns a String containing that
integer's binary representation. For example, the call of printBinary(44) should return "101100" .