functions homework

public class FunctionsHW {

    /*
    q1-1
    this method find the number of instances of a digit in a number
     */
    public static int numOfInstances(int a, int numToFind) {
        int counter = 0;
        while (a > 0) {
            if (a % 10 == numToFind) {
                counter += 1;
            }
            a /= 10;
        }
        return counter;
    }//end of numOfInstances

    /*
    q1-2
    this method find the number of instances of a digit in array
    by using method numOfInstances
     */
    public static int arrInstances(int[] array, int numToFind) {
        int counter = 0;
        for (int i = 0; i < array.length; i += 1) {
            counter += numOfInstances(array[i], numToFind);
        }
        return counter;
    }//end of arrInstances method

    /*
    q2
    this method takes two arrays and return a new array
    with the similar values of the two given arrays
     */
    public static int[] similarValues(int[] arr1, int[] arr2) {
        int[] similarArray = new int[(arr1.length + arr2.length) / 2];
        for (int i = 0; i < arr1.length; i += 1)
            for (int j = 0; j < arr2.length; j += 1) {
                if (arr1[i] == arr2[j])
                    similarArray[i] = arr1[i];
            }
        return similarArray;
    }

    /*
    added a method to print the array
     */
    public static String printArray(int[] arr) {
        String array = "";
        for (int i = 0; i < arr.length; i += 1)
            if (arr[i] != 0)
                array += arr[i] + "\t";

        return array;
    }


    //main
    public static void main(String[] args) {
        int[] array1 = {33, 2, 3, 4, 55, 66, 64, 63, 6};//6 appears 5 times
        int[] array2 = {3, 4, 66, 7, 8, 9, 10, 11, 12}; // 3,4,66

        System.out.println(numOfInstances(1222344, 2));
        System.out.println(arrInstances(array1, 6));
        System.out.println(printArray(similarValues(array1, array2)));
    }//end of main
}