C language implementation!20000 in 4 seconds

#include <stdio.h>
#include <windows.h>

#define FACTORIAL 10000

int main()
{
    
	unsigned char ucResult[50000] = {
     0 };
	int iMul = 2;
	int iTmpResult = 0;
	int iTmpMul = 0;
	int iIdx = 0;
	int iCarry = 0;
	int iTmpInter = 0;
	ucResult[0] = 1;

	while (iMul <= FACTORIAL)
	{
    
		while (iIdx < sizeof(ucResult))
		{
    
			iTmpMul = ucResult[iIdx];
			iTmpInter = iMul * iTmpMul + iCarry;
			ucResult[iIdx] = iTmpInter % 10;
			iCarry = iTmpInter / 10;
			
			++iIdx;
		}
		iIdx = 0;
		++iMul;
	}

	int i = sizeof(ucResult) - 1;
	while (i >= 0)
	{
    
		printf("%d", ucResult[i]);
		--i;
	}

	system("pause");

	return(0);
}

(完)