Description：

Given a 32-bit signed integer, reverse digits of an integer.

Example1:

Input: 123 Output: 321

Example2:

Input: -123 Output: -321

Example3:

Input: 120 Output: 21

提交程式碼：

int reverse(int x) {
 //int正數最大2147483647 負數最大-2147483648
	int tmp=x,flag;
	int i=0,x_reverse=0,len=0;
	int nums[10]
 
;

	//是個正數
	if (x > 0)
	{
		//將這個數存到一個數組裡面
		while (tmp != 0)
		{
			nums[i++] = tmp % 10;
			tmp /= 10;
			len++;
		}

		//看有沒有越界
		if (len == 10)
		{
			if (nums[0] > 2)	return 0;
			else if (nums[0] == 2)
			{
				tmp = 0;
				for (i = 1; i <len; i++)
					tmp = tmp * 10 + nums[i];

				if (tmp > 147483647
 
)	return 0;
			}
		}
		tmp = 0;
		for (i = 0; i <len; i++)
			tmp = tmp * 10 + nums[i];
		return tmp;
	}

	//是個負數
	else
	{
		while (tmp != 0)
		{
			nums[i++] = -1*(tmp % 10);
			tmp /= 10;
			len++;
		}

		//看有沒有越界
		if (len == 10)
		{
			if (nums[0] > 2)	return 0;
			else if (nums[0] == 2)
			{
				tmp = 0;
				for
 
 (i = 1; i <len; i++)
					tmp = tmp * 10 + nums[i];

				if (tmp > 147483648)	return 0;
			}
		}
		tmp = 0;
		for (i = 0; i <len; i++)
			tmp = tmp * 10 + nums[i];
		return -1 * tmp;
	}
}

執行結果：