7Boom_to_file

package fileWork;

import java.io.File;
import java.io.IOException;
import java.io.PrintWriter;

public class Main {
    public static void main(String[] args) throws IOException {
        int userNum= 100;
        String fileName = "boom.txt"; //for test
        sevenBoom(fileName, userNum);

    }

    // file path C:\res\boomb.txt
    public static void sevenBoom(String fileName, int userNum) throws IOException {
        //creating new file and its PrintWriter to write in
        File f = new File("C:\\res\\"+fileName);
        f.createNewFile();
        PrintWriter pw = new PrintWriter(f);
        //go throught all numbers untill user's number
        for (int i = 1; i<userNum;i+=1) {
            //using help function which check if a number is 7Boom
            if (containSeven(i)) {
                pw.print("7Boom!");
                pw.println();
            } else {
                pw.print(i + " ");
            }
        }
        pw.close();
    }

    public static boolean containSeven(int num) {
        int temp;
        //true for numbers which could be divided by 7
        if (num%7==0&&num%10!=0){
            return true;
        }
        //thue for numbers which contains digit 7
        while (num != 0) {
            temp = num % 10;
            if (temp%7==0&&temp%10!=0){
                return true;
            }
            num /= 10;
        }
        // for all others false
        return false;
    }
}