Timus 1601. AntiCAPS 修正大写句子

The blonde Angela has a new whim: internet chats. Of course, as any blonde, she writes her messages using the upper case. You are the moderator of Angela's favorite chat and you're fed up with her upper-case messages. The problem is that Angela does not respond to your warnings. You decided to write a simple antiCAPS corrector, which would make Angela's messages readable.

The correction rules are very simple:

1. Sentences in a message consist of words, spaces and punctuation marks.
2. Words consist of English letters.
3. Sentences end with a full stop, exclamation mark, or question mark.
4. The first word of each sentence must start with a capital letter, and all other letters of the sentence must be lowercase.

Input

You are given Angela's message, which consists of uppercase English letters, spaces, line breaks and punctuation marks: full stops, commas, dashes, colons, exclamation and question marks. Total length of message is not exceeding 10000 symbols.

Output

Output the corrected message.

Sample

input	output
HI THERE! HOW DID YOU KNOW I AM A BLONDE?	Hi there! How did you know i am a blonde?

就是修正个全是大写的句子。

这里注意一点(as in codes' comment)：

keep the state, because blonde would do anything, and put the comma, in one line, and start typing another line.

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

void toLowerCase(string &s, bool &senBegin)
{
	for (unsigned i = 0; i < s.size(); i++)
	{
		if (' ' == s[i]) continue;
		if (senBegin) 
		{
			if ('A' <= s[i] && s[i] <= 'Z' || 'a' <= s[i] && s[i] <= 'z') 
			{
				s[i] = toupper(s[i]);
				senBegin = false;
			}
			continue;
		}
		if ('.' == s[i] || '?' == s[i] || '!' == s[i]) senBegin = true;
		s[i] = tolower(s[i]);
	}
}

int AntiCAPS1601()
{
	string s;
	bool senBegin = true;//keep the state, because blonde would do anything, and put the comma, in one line, and start typing another line.
	while (getline(cin, s))
	{
		toLowerCase(s, senBegin);
		cout<<s<<endl;
	}
	return 0;
}