how to convert to uppcase all the elements in a vector in C++

I want to display all the elements in a vector. My code displays all elements but converts to uppercase just the last one.

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


int main()
{
    string words;
    string it;
    vector<string>list_words;

    while (cin>>words)
        list_words.push_back(words);
            for (auto it = words.begin(); it != words.end() && !isspace(*it); ++it)
                *it = toupper(*it);
                cout<<list_words.size()<<endl;
                cout<<words<<endl;
                



    return 0;
}