可乐商店问题
题目大意：
Once upon a time, there is a special coco-cola store. If you return three empty bottles to the shop,
you’ll get a full bottle of coco-cola to drink. If you have n empty bottles right in your hand, how many
full bottles of coco-cola can you drink?
要求：
Input
There will be at most 10 test cases, each containing a single line with an integer n (1 ≤ n ≤ 100). The
input terminates with n = 0, which should not be processed.
Output
For each test case, print the number of full bottles of coco-cola that you can drink.
Spoiler
Let me tell you how to drink 5 full bottles with 10 empty bottles: get 3 full bottles with 9 empty
bottles, drink them to get 3 empty bottles, and again get a full bottle from them. Now you have 2
empty bottles. Borrow another empty bottle from the shop, then get another full bottle. Drink it, and
finally return this empty bottle to the shop
样例输入：
Sample Input
3
10
81
0
Sample Output
1
5
40
题目分析：
这是一道数学问题，考验的是数学思考能力。根据题中给出的示例可以让我们更清楚的计算出结果。用到了取余数与取除数（n=n/3+n%3）,每次都要统计所喝的瓶子的总数量。
如果还剩两个空瓶子时可以借一个空瓶子再喝一瓶可乐。当n=0时不执行，程序结束。
程序代码：
1 #include<cstdio>
2 #include<iostream>
3 using namespace std;
4
5 int n[100];
6
7 int main()
8 {
9 int n,a;
10 while(scanf("%d",&n)) //输入空瓶子数量
11 {
12 if(n==0) //当n=0时程序结束
13 break;
14 a=0;
15 while(n>2) //n>2时做此循环，统计所喝饮料的总数a
16 {
17 a+=n/3;
18 n=n/3+n%3;
19 }
20 if(n==2)
21 a++;
22 cout<<a<<endl;
23 }
24 return 0;
25 }
心得：
这道题主要考数学思考能力，把要做的公式想到，题目就变得简单了，而且题中还给了提示。虽然一道很简单的题目，我却做了一个多小时，有一处错误总也改不对，后来静下心来终于改对了，是一处很小的错误，这提醒我以后写程序时要注意细节，不要大体过了就算了。