一行文本中的最长单词

问题：已知 string sentence="We were her pride of 10 she named us: Benjamin, Phoenix, the  Pordigal and perspicacious pacific Suzanne.";

要求：计算sentence中有多少个单次，并指出其中最长和最短的单词，如果有多个，则将它们全部输出。

解法：使用find_first_of 和find_first_not_of，寻找到单词的起始位置，以剔除标点；
    使用vector存放最长和最短单词：通过贪心算法，寻找“最**”单词

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

int main(){
	string sentence="We were her pride of 10 she named us: Benjamin, Phoenix, the Pordigal and perspicacious abcdefghijklmnopqrstuvwxyz pacific Suzanne.";

	string separators="	f
v:,. ";//作为分隔符
	
	string::size_type maxLen,minLen,wordLen,count=0;
	
	string word;

	vector<string> longestWords, shortestWords;

	string::size_type startPos=0,endPos=0;

	while( (startPos=sentence.find_first_not_of(separators,endPos) ) !=string::npos){//npos是一个常数，用来表示不存在的位置
		++count;
		

////////////////////////////////////////////////////////////////////////////////////////////

		//找到下一个单词的结束位置
		endPos=sentence.find_first_of(separators,startPos);
		
		//若找不到下一个分隔符，则说明该单词为最后一个单词
		if(endPos==string::npos){
			wordLen=sentence.size()-startPos;
		}
		else{
			wordLen=endPos-startPos;
		}

		//注意这里不要是sentence.begin()+endPos;有可能endPos为string::npos;
		//word.assign(sentence.begin()+startPos, sentence.begin()+startPos+wordLen);
		word=sentence.substr(startPos, wordLen);//从startPos开始，wordLen个字母构成的子串
		
/////////////////////////////////////////////////////////////////////////////////////////

		if(count==1){
			longestWords.push_back(word);
			shortestWords.push_back(word);
			maxLen=minLen=wordLen;
		}else{
			if(wordLen>maxLen){
				longestWords.clear();
				longestWords.push_back(word);
				maxLen=wordLen;
			}else if(wordLen==maxLen){
				longestWords.push_back(word);
			}
			
			if(wordLen<minLen){
				shortestWords.clear();
				shortestWords.push_back(word);
				minLen=wordLen;
			}else if(wordLen==minLen){
				shortestWords.push_back(word);
			}

		}// end of else


	}//end of while

	//输出单词数目
	cout<< "word amount: "<< count <<endl;
	vector<string>::iterator iter;

	//输出最长单词
	cout<< "longest words: "<<endl;
	iter=longestWords.begin();

	while( iter!=longestWords.end()  )
		cout<< *iter++ <<endl;

	//输出最短单词
	cout<< "shortest words: "<<endl;
	iter=shortestWords.begin();

	while(iter!=shortestWords.end())
		cout<< *iter++ <<endl;


	return 0;
}