How to change each word in a string vector to upper case [duplicate]

This question already has an answer here:

• Convert a String In C++ To Upper Case 21 answers

I was inquiring about reading a sequence of words and storing the values in a vector. Then proceed to change each word in the vector to uppercase and print the out put with respect to eight word to a line. I think my code is either slow or running infinitely as i can't seem to achieve an output.

using namespace std;

int main(){
    string word;
    vector<string> text;
    while(getline(cin, word)){
        text.push_back(word);
    }
        for (auto index = text.begin(); index != text.end(); ++index){
            for( auto it = word.begin(); it != word.end(); ++it)
                *it = toupper(*it);
            /*cout<< index << " " << endl;*/
            }

    for (decltype(text.size()) i = 0; i != 8; i++)
        cout<< text[i] << endl;

    return 0;
}