学步园

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)

Mid-Central USA 2001

#include <stdio.h>

int main()
{
    double sum_;
    double result_;
    int n;
    
    while ((~scanf("%lf", &sum_)) && sum_ != 0.00   )
    {
        result_ = 0.00;
        for (n=2;result_ <= sum_ ; n++)
        {
            result_ += 1.00/(double)n;//注意类型的转换
        }
        printf("%d card(s)\n", n-2);
    }
    return 0;
}