LeetCode之7_Reverse Integer

题目原文：

 

Reverse digits of an integer.

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

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分析：将整数倒序，符号不变，需要注意的是当改变后的值超出整数的可表示范围后，返回0.

 

代码：

 

//Reverse digits of an integer.
//
//Example1: x = 123, return 321
//Example2: x = -123, return -321

#include <iostream>
using namespace std;

class Solution {
public:
int reverse(int x) {
int nFlag = 1;
int nRet = 0;
int nLeft =0;
int nOld = 0;

if (x < 0)
{
x *= -1;
nFlag = -1;
}
while (x != 0)
{
nLeft = x % 10;
x = x/10;
nOld = nRet;
nRet = nRet *10 + nLeft;
}

if (nOld  != nRet / 10)
{
return 0;
}

nRet *= nFlag;
return nRet;
}
};