二进制表示-LintCode

给定一个数将其转换为二进制（均用字符串表示），如果这个数的小数部分不能在 32 个字符之内来精确地表示，则返回 “ERROR”。
样例：
n = “3.72”, 返回 “ERROR”.
n = “3.5”, 返回 “11.1”.

#ifndef C180_H#define C180_H#include<iostream>#include<string>using namespace std;class Solution {public:    /**    *@param n: Given a decimal number that is passed in as a string    *@return: A string    */    string binaryRepresentation(string n) {        // wirte your code here        if (n.empty())            return NULL;        int len = n.size();        int pos = 0;        for (int i = 0; i < len; ++i)        {            if (n[i] == '.')            {                pos = i;                break;            }        }        string Integer = n.substr(0,pos);        string Decimal = n.substr(pos + 1, len - 1 - pos);        int size = Decimal.size();        long long intNum = stoll(Integer);        long long DecNum = stoll(Decimal);        double num = DecNum;        for (int j = 1; j <= size; ++j)        {            num /= 10;        }        int count = 0;        string sum;        while (num != 0)        {            count++;            num *= 2;            if (num >= 1)            {                num -= 1;                sum += "1";            }            else            {                sum += "0";            }        }        if (count > 32)            return "ERROR";        else        {            string str;            if (intNum == 0)                str= "0";            for (int i = intNum; i; i = i / 2)            {                str += (i % 2 ? "1" : "0");            }            reverse(str.begin(), str.end());            if (sum.empty())                return str;            return str + "." + sum;        }    }};#endif