public class NumberOfDigitsDivisibleBy3
1: //NumberOfDigitsDivisibleBy3.java
2:
3: public class NumberOfDigitsDivisibleBy3
4: {
5: public static void main(String[] args)
6: {
7: System.out.println("\nTesting numberOfDigitsDivisibleBy3() ...");
8: System.out.print(numberOfDigitsDivisibleBy3(123456));
9: System.out.println();
10: System.out.print(numberOfDigitsDivisibleBy3(363639));
11: System.out.println();
12: System.out.print(numberOfDigitsDivisibleBy3(124578));
13: System.out.println();
14: System.out.print(numberOfDigitsDivisibleBy3(100008));
15: System.out.println();
16: System.out.print(numberOfDigitsDivisibleBy3(0));
17: System.out.println();
18: System.out.print(numberOfDigitsDivisibleBy3(9));
19: System.out.println();
20: System.out.print(numberOfDigitsDivisibleBy3(12));
21: System.out.println();
22: }
23:
24: //Computes and returns the number of digits in n that are divisible by 3
25: public static int numberOfDigitsDivisibleBy3(int n)
26: {
27: if (n < 10)
28: {
29: return (n % 3 == 0) ? 1 : 0;
30: }
31: else
32: {
33: return numberOfDigitsDivisibleBy3(n / 10)
34: + numberOfDigitsDivisibleBy3(n % 10);
35: }
36: }
37: }