POJ-1003 Hangover-紙牌疊放

How far can you make a stack of cards overhang a table? If you have one card, you can create a maximum overhang of half a card length. (We're assuming that the cards must be perpendicular to the table.) With two cards you can make the top card overhang the bottom one by half a card length, and the bottom one overhang the table by a third of a card length, for a total maximum overhang of 1/2 + 1/3 = 5/6 card lengths. In general you can make n cards overhang by 1/2 + 1/3 + 1/4 + ... + 1/(n + 1) card lengths, where the top card overhangs the second by 1/2, the second overhangs tha third by 1/3, the third overhangs the fourth by 1/4, etc., and the bottom card overhangs the table by 1/(n + 1). This is illustrated in the figure below.

The input consists of one or more test cases, followed by a line containing the number 0.00 that signals the end of the input. Each test case is a single line containing a positive floating-point number c whose value is at least 0.01 and at most 5.20; c will contain exactly three digits.

For each test case, output the minimum number of cards necessary to achieve an overhang of at least c card lengths. Use the exact output format shown in the examples.

1.00
3.71
0.04
5.19
0.00

3 card(s)
61 card(s)
1 card(s)
273 card(s)

#include <iostream>  
using namespace std;  
int main()  
{  
    int i;  
    double length,sum;  
  
    while(1)  
    {  
        cin >> length;  
        sum = 0;  
        if(length == 0.00)  
            break;  
        for(i = 1; i < 300; i++)  
        {  
            sum += 1.0/(i+1);  
            if(sum >= length)  
            {  
                cout << i << " card(s)\n";  
                break;  
            }  
        }  
    }  
    return 0;  
}