// Program to test solutions to problem #2 on the cse143 midterm, spring 2018.
// Note that it does not test whether the method throws proper exceptions.
// Fill in your solution to doubleDigit, then compile and run the program.

import java.util.*;
import java.io.*;

public class Test2 {
    public static int doubleDigit(int n, int d) {
        // fill in your solution here
        // you can also rename the parameters above
    }

    // this is the sample solution
    public static int doubleDigit2(int n, int d) {
        if (d < 0 || d > 9) {
            throw new IllegalArgumentException();
        }
        if (n < 0) {
            return -doubleDigit2(-n, d);
        } else if (n == 0) {
            return 0;
        } else if (n % 10 == d) {
            return doubleDigit2(n / 10, d) * 100 + d * 11;
        } else {
            return doubleDigit2(n / 10, d) * 10 + n % 10;
        }
    }

    private static int testCount;
    private static int failCount;

    public static void main(String[] args) {
        test(3797, 7);
        test(2, 2);
        test(0, 0);
        test(8, 6);
        test(55, 2);
        test(33, 3);
        test(-101, 1);
        test(323, 3);
        test(2001, 0);
        test(12345, 6);
        test(72773, 7);
        test(3445, 5);
        test(54224, 4);
        test(-624243, 4);
        test(5340909, 0);
        test(121121, 1);

        if (failCount == 0) {
            System.out.println("passed all " + testCount + " tests");
        } else {
            System.out.println("failed " + failCount + " of " + testCount + 
                               " tests");
        }
    }

    public static void test(int n, int d) {
        testCount++;
        int result1 = doubleDigit2(n, d);
        System.out.println("doubleDigit(" + n + ", " + d + ") = " + result1);
        boolean fail = false;
        try {
            int result2 = doubleDigit(n, d);
            if (result1 != result2) {
                fail = true;
                System.out.println("yours = " + result2);
            }
        } catch (RuntimeException e) {
            System.out.println("threw " + e);
            fail = true;
        }
        if (!fail) {
            System.out.println("passed");
        } else {
            failCount++;
            System.out.println("failed");
        }
        System.out.println();
    }
}