【王道JAVA】【程序 43 求奇數個數】

題目：求 0—7 所能組成的奇數個數。

public class WangDao {
	public static void main(String[] args) {
		int count = 0, sum = 0;
		for (int digit = 1; digit <= 8; digit++) {
			switch (digit) {
			case 1:
				count = 4;	// 1, 3, 5, 7
				break;
			case 2:
				count = 4 * 6;	// 個位數4、十位數6
				break;
			case 3:
				count = 4 * 6 * 6;
				break;
			case 4:
				count = 4 * 6 * 6 * 5;
				break;
			case 5:
				count = 4 * 6 * 6 * 5 * 4;
				break;
			case 6:
				count = 4 * 6 * 6 * 5 * 4 * 3;
				break;
			case 7:
				count = 4 * 6 * 6 * 5 * 4 * 3 * 2;
				break;
			case 8:
				count = 4 * 6 * 6 * 5 * 4 * 3 * 2 * 1;
				break;
			}
			sum += count;
			System.out.println(digit + "-digit number of 0-7: " + count);
		}
		System.out.println("The odd sum is " + sum);
	}
}