import java.util.Arrays;

public class Main {

    public static void main(String[] args) {
        String[] stackSample = {"a", "b", "c", "a", "tacos"};
        String needleSample = "a";
        System.out.println(countOccurrences(stackSample, needleSample));
        System.out.println(firstOccurrence(stackSample, needleSample));
        int [] newArray = {1, 3, 5, 7};
        System.out.println(Arrays.toString(multiplyArray(newArray)));
    }

    public static int countOccurrences(String[] stack, String needle) {
        int count = 0;
        for (int i=0; i < stack.length; i++) {
            if (stack[i].equals(needle)) {
                count +=1;
            }
        }
        return count;
    }

    public static int firstOccurrence(String[] stack, String needle) {
        for (int i = 0; i < stack.length; i++) {
            if (stack[i].equals(needle)) {
                return i;
            }

        }
        return -1;
    }

    public static int[] multiplyArray(int[] values) {
        int[] result = new int[values.length];
        for (int i = 0; i < values.length; i++) {
            result[i] = values[i] * 2;
        }
        return result;

    }
}