leetcode_7_Reverse Integer，leetcode_7_reverse

leetcode_7_Reverse Integer，leetcode_7_reverse
描述:

Reverse digits of an integer.

Example1: x = 123, return 321
Example2: x = -123, return -321

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Have you thought about this?

Here are some good questions to ask before coding. Bonus points for you if you have already thought through this!

If the integer's last digit is 0, what should the output be? ie, cases such as 10, 100.

Did you notice that the reversed integer might overflow? Assume the input is a 32-bit integer, then the reverse of 1000000003 overflows. How should you handle such cases?

For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

Update (2014-11-10):
Test cases had been added to test the overflow behavior.

思路：

思路倒是簡潔明了，將整數的非符號部分的各位儲存到一個數組裡面，然後將各位組裝起來就成為一個新的整數。當然，溢出，符號都是需要考慮的。

代碼：

int reverse(int x) {        int i=0;        int num[20]={0};        long sum=0;        int flag=0;        if(x<0)            {x=-x;flag=1;}        while(x!=0)        {            num[i++]=x%10;            x/=10;        }        for(int j=0;j<i;j++)        {            sum=sum*10+num[j];        }        if(flag)        sum=-sum;        return sum;            }

結果：