reverse integer

LeetCode 题目：

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?

Throw an exception? Good, but what if throwing an exception is not an option? You would then have to re-design the function (ie, add an extra parameter).

/**reverse integer * Created by a819 on 2017/8/2. */public class Solution2 {    public int reverse(int x){        StringBuilder sb=new StringBuilder();        int flag=0;                //首次出现0的标志        if(x==0)            return 0;        String y=String.valueOf(x);//将x转换为字符串        if(y.charAt(0)=='-'){            sb.append('-');            for(int i=y.length()-1;i>0;i--){            //第一次出现0不处理            if(y.charAt(i)==0&flag==0)                continue;            else {                sb.append(y.charAt(i));                flag=1;                }            }        }        else{            for(int i=y.length()-1;i>=0;i--){                if(y.charAt(i)==0&flag==0)                    continue;                else {                    sb.append(y.charAt(i));                    flag=1;                }            }        }        //如果越界直接返回0        try {        int res=Integer.parseInt(sb.toString());        return res;}        catch(Exception e){            return 0;        }    }/*    public static void main(String[] args) {        int x=1;        Solution2 s2=new Solution2();        System.out.println(s2.reverse(x));    }    */}