Even odd counter

The problem

Write a program with a method named isEven that accepts an int argument. The method should return true if the argument is even, or false if otherwise. The program 's main method should use a loop to generate 100 random integers. It should use the isEven method to determine whether each random number is even, or odd. When the loop is finished, the program should display the number of even numbers that were generated, and the number of odd numbers.

Breaking it down

Write isEven method

/**
 * @param num to check
 * @return true if the num is true otherwise false
 */
public static boolean isEven(int num) {
    boolean isEvenNumber = false;

    if ((num % 2) == 0) {
        isEvenNumber = true;
    }
    return isEvenNumber;
}

Putting it together

private static int RANDOM_NUMBERS = 100;

public static void main(String[] args) {

    int evenNumberCount = 0;
    int oddNumberCount = 0;

    Random randomValue = new Random();

    // Generate 100 random numbers.
    for (int i = 1; i <= RANDOM_NUMBERS; i++) {
        // Determine if the number was even or odd.
        if (isEven(randomValue.nextInt(i))) {
            evenNumberCount++;
        } else {
            oddNumberCount++;
        }
    }

    System.out.println("Number of even numbers: " + evenNumberCount);
    System.out.println("Number of odd numbers: " + oddNumberCount);

}

Output

Number of even numbers: 34
Number of odd numbers: 66

Unit tests

@Test
public void test_isEven_even () {

    assertTrue(EvenOddCounter.isEven(10));
}

@Test
public void test_isEven_odd () {

    assertFalse(EvenOddCounter.isEven(9));
}

Level Up

Use a JOptionPane to display the output
Find and output the percentage of even and odd numbers
Try generating a list of random numbers using using Java 8 techniques