3个骰子求和

// 3RandomSum.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <stdlib.h>  
#include "time.h"
using namespace std;

#define myMax(x,y)  ( x>y?x:y )
#define myMin(x,y)  ( x<y?x:y )

int _tmain(int argc, _TCHAR* argv[])
{
	int iSum = 0;
	while (scanf_s("%d", &iSum))
	{
		int iMin = 1;
		int s1 = 0;
		int s2 = 0;
		int s3 = 0;
		srand(time(NULL) * 10);
		if (iSum <= 18 && iSum >= 3)
		{
			do
			{
				int iMax = myMin(6, iSum - 2);
				if (iMax > iMin)
				{
					s1 = iMin + rand() % iMax;
				}
				else
				{
					s1 = 1;
				}

				int iLeft = iSum - 2 - s1;
				iMax = myMin(6, iLeft);
				if (iMax > iMin)
				{
					s2 = iMin + rand() % iMax;
				}
				else
				{
					s2 = 1;
				}
				s3 = iSum - s1 - s2;
			} while (s1 > 6 || s2 > 6 || s3 > 6);
			printf("%d = %d + %d + %d", iSum, s1, s2, s3);
		}
		else
		{
			printf("input error,please input 3 to 18");
		}
		
	}
	return 0;
}