输出1到最大的n位数

例如：输入3，输出 1 ~ 999，必须考虑大数问题

/* 打印从 1到最大的n位数 */
bool Increment(char *number)
{
	bool isOverflow = false;
	int nTakeOver = 0;
	int nLength = strlen(number);

	for (int i = nLength-1; i >= 0; i--)
	{
		int nSum = number[i] - '0' + nTakeOver; //初始置为 0
		if (i == nLength - 1) //第一位保证必须是 1
			nSum++;
		if (nSum >= 10) 
		{
			if (i == 0)
				isOverflow = true;
			else
			{
				nSum -= 10;
				nTakeOver = 1;
				number[i] = '0' + nSum;
			}
		}
		else
		{
			number[i] = '0' + nSum;
			break;
		}
	}
	return isOverflow;
}

void PrintNumber(char *number)
{
	bool isBeginning0 = true;
	int nLength = strlen(number);

	for (int i = 0; i < nLength; ++i)
	{
		if (isBeginning0 && number[i] != '0') //找到第一位不为0的数字字符
			isBeginning0 = false;
		if (!isBeginning0)  //从第一位不为0的数字字符开始打印
			printf("%c", number[i]);
	}
	printf("\t");
}

void PrintToMaxOfNDigits(int n)
{
	if (n <= 0)
		return;
	char *number = new char[n+1]; //开辟n+1大小的空间
	memset(number, '0', n); //前n位置0
	number[n] = '\0'; //末尾置为'\0'

	while (!Increment(number))
		PrintNumber(number);

	delete []number;

}

//////////////////////////////////////////////////////////////////////////
/* 方法二 */
void Print1ToMaxOfNDigitsREcursively(char *number, int length, int index)
{
	if (index == length - 1)
	{
		PrintNumber(number);
		return;
	}
	for (int i=0; i<10; ++i)
	{
		number[index+1] = i + '0';
		Print1ToMaxOfNDigitsREcursively(number, length, index+1);
	}
}

void Print1ToMaxOfNDigits(int n)
{
	if (n<=0)
		return;
	char *number = new char[n+1];
	number[n] = '\0';

	for (int i=0; i<10; ++i)
	{
		number[0] = i + '0';
		Print1ToMaxOfNDigitsREcursively(number, n, 0);
	}
	delete []number;
}

void main()
{
	int n = 3;
//	PrintToMaxOfNDigits(n);
	Print1ToMaxOfNDigits(n);
	
}

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