My Code is Working in My g++ Compiler But Not Working on ideone by which i have to Submit on SPOJ

This is Solution To Problem Hangover on POJ and i think the Logic is Correct but My Solution is not Working on POJ Compiler but it's Working Correct on My g++ Compiler.What's Wrong with My Solution. Here is the Problem Link. http://poj.org/problem?id=1003

I Tried To think what is Wrong and i think there is something Wrong how poj take input output and how i am providing.

#include<iostream>
#include<cstdlib>
using namespace std;

int main()
{
    float desired=1.00;
    while(1)
    {
        cin>>desired;
        if(desired!=0 and desired<=5.20 and desired>=0.01)
        {
            float sum=0;
            int denominator=2;
            float num=1;
            int total=0;
            while(sum<=desired)
            {
                num=1.00/denominator;
                sum+=num;
                total+=1;
                ++denominator;
            }
            cout<<total<<"\n";
        }
        else
            exit(0);
        }
    return 0;
}

I expect my Solution is True but i can't think where i am wrong.