7-leetcode-Reveser Integer

问题描述：

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

Example 1:

Input: 123Output:  321

Example 2:

Input: -123Output: -321

Example 3:

Input: 120Output: 21

Note:
Assume we are dealing with an environment which could only hold integers within the 32-bit signed integer range. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.

解题必须了解这个：

整数的取值范围：-2147483648-2147483648 

char : -128-127

short int:-32767-32768

unsigned short:0-65536

class Solution {public:    int reverse(int x) {        int revInteger = 0;        int flat = x>0?1:-1;        x = x > 0 ? x : -x;        while( x > 0){            if(revInteger*10.0+x%10 > 2147483647) return 0;            revInteger = revInteger*10+(x%10);            x /= 10;        }        return revInteger*flat;    }};