7의 개수

import java.util.*;

class Solution {
    public int solution(int[] array) {
        int answer = 0;

        for (int i = 0; i < array.length; i++) {
            int num = array[i];

            while (num > 0) {
                if (num % 10 == 7) {
                    answer++;
                }
                num /= 10;
            }
        }
        return answer;
    }
}