Reverse Integer--LeetCode

题目：

Reverse digits of an integer.

Example1: x = 123, return 321

Example2: x = -123, return -321

思路：如果是整数，直接反转，如果是负数，那么反转以后记得添加负号

int ReverseInteger(int value)
{
	int reserve=0;
	int key;
	int flag=1;
	if(value<0)
		flag = -1;
	key = flag*value;
	while(key)
	{
		reserve = reserve*10+key%10;
		key = key/10;
			
	} 
	return flag*reserve;
}

上述这个问题是没有考虑边界的想象

int ReverseInt(int n)
{
	int flag = 1;
	int value = n;
	if(n < 0)
	{
		flag = -1;
		value = -n;
	}
	int result =0;
	while(value)
	{
		int temp = value %10;
		if(temp > (numeric_limits<int>::max()/10 - result))
			return flag == 1? numeric_limits<int>::max():numeric_limits<int>::min();
		result = result*10 +temp;
		value /= 10;
	}
	return flag*result;
}