The Famous Clock
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 1399 Accepted Submission(s): 940
Problem Description
Mr. B, Mr. G and Mr. M are now in Warsaw, Poland, for the 2012’s ACM-ICPC World Finals Contest. They’ve decided to take a 5 hours training every day before the contest. Also, they plan to start training at 10:00 each day since the World Final Contest will do so. The scenery in Warsaw is so attractive that Mr. B would always like to take a walk outside for a while after breakfast. However, Mr. B have to go back before training starts, otherwise his teammates will be annoyed. Here is a problem: Mr. B does not have a watch. In order to know the exact time, he has bought a new watch in Warsaw, but all the numbers on that watch are represented in Roman Numerals. Mr. B cannot understand such kind of numbers. Can you translate for him?
Input
Each test case contains a single line indicating a Roman Numerals that to be translated. All the numbers can be found on clocks. That is, each number in the input represents an integer between 1 and 12. Roman Numerals are expressed by strings consisting of uppercase ‘I’, ‘V’ and ‘X’. See the sample input for further information.
Output
For each test case, display a single line containing a decimal number corresponding to the given Roman Numerals.
Sample Input
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
XII
Sample Output
Case 1: 1
Case 2: 2
Case 3: 3
Case 4: 4
Case 5: 5
Case 6: 6
Case 7: 7
Case 8: 8
Case 9: 9
Case 10: 10
Case 11: 11
Case 12: 12
Source
分析：这种Case的模式不太会写，然后我直接枚举出来，WA了，我也不知道为啥错了，然后看别人写，去统计，感觉自己好傻，根本没必要那样！
下面给出AC代码：
#include <bits/stdc++.h>
using namespace std;
int main()
{
char s[];
int k=;
int ans;
while(gets(s))
{
ans=;
int len=strlen(s);
for(int i=;i<len;i++)
{
if(s[i]=='I')ans++;
if(s[i]=='V')ans=-ans;
if(s[i]=='X')ans=-ans;
}
printf("Case %d: %d\n",++k,ans);
}
return ;
}