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

int main()
{
vector<string> text; //hold all word
string word;
int max=0;

cout<<"please input text :"<<endl;
//read line......

while(1)
{
cin>>word;
if(max < word.size())
max = word.size();
text.push_back(word);

if(cin.get()=='\n') break;
}

//output.............

int size=text.size();
cout<<"longest word : \n";
for(int i=0; i<size; i++)
if(text[i].size()==max)
cout<<'\t'<<text[i]<<'\n';
cout<<"lengh : "<<max<<endl;

system("pause");
return 0;
}

把我前面的简化了一下