5-23 幣值轉換 (20分)

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;

char ans[100];

int main()
{
	bool b;
	int l, num, n, d;
	while (scanf("%d", &num) == 1)
	{
		memset(ans, 0, sizeof(ans));
		d = 0;
		l = 0;
		b = true;
		if (num == 0)
		{
			printf("a\n");
			continue;
		}
		while (num)
		{
			n = num % 10;
			num /= 10;
			if (d == 4)
			{
				b = true;
				ans[l++] = 'W';
			}
			else if (d == 8)
			{
				b = true;
				ans[l++] = 'Y';
			}
			if (b == false && n == 0)
			{
				ans[l++] = 'a';
				b = true;
			}
			if (n)
			{
				if (d % 4 == 1) ans[l++] = 'S';
				else if (d % 4 == 2) ans[l++] = 'B';
				else if (d % 4 == 3) ans[l++] = 'Q';
				b = false;
				if (!(d == 1 && n == 1)) ans[l++] = 'a' + n;
			}
			d++;
		}
		reverse(ans, ans + l);
		printf("%s\n", ans);
	}
	return 0;
}