I have attached a screenshot of the error on line 64 sort. The error states: identifier "sort" is undefined. Had to remove some info. due to word count. 2) Sort the 2 or 3 parallel vectors in...

Need to remove unnecessary vector from the code which is not used.

And also need to sort the 2 03 3 parallel vectors which has been used in the code.

As 3rd vector is removed 2nd vector is left to be sorted, so revised code along with sorted values of all_words_counts.

#include
#include
#include
#include
#include
#include
#include
#include

using namespace std;

const string empty_string = "";
vector getWords(const string& text);
int findWord(const vector& words, const string& word);
int main()
{
    vector all_words;
    vector all_word_counts;
    //vector<>> all_line_numbers;
    string input_file_name;
    cout < "source="" file="" name?="">
    getline(cin, input_file_name);
    ifstream finp;
    finp.open(input_file_name);
    assert(finp.good());
    string line;
    int word_counter = 0;
    int max_word_length = 0;
    int max_word_count = 0;
    int line_number = 0;
    getline(finp, line);
    while (!finp.eof())
    {
        line_number++;
        vector words = getWords(line);
        word_counter += words.size();
        for (int idx = 0; idx < words.size();="">
        {
            int widx = findWord(all_words, words[idx]);
            if (widx == -1)
            {
                cout < words[idx]=""><>
                all_words.push_back(words[idx]);
                all_word_counts.push_back(1);
                vector word_line_numbers;
                word_line_numbers.push_back(line_number);
              // all_line_numbers.push_back(word_line_numbers);
                if (words[idx].length() > max_word_length)
                   max_word_length = words[idx].length();

            }
            else
            {
                all_word_counts[widx]++;
              // all_line_numbers[widx].push_back(line_number);
                if (all_word_counts[widx] > max_word_count)
                    max_word_count = all_word_counts[widx];
            }
        }
        getline(finp, line);
    }
 sort(all_word_counts.begin(),all_word_counts.end());
    finp.close();
    string output_file_name = input_file_name;
    string time_as_string = to_string(static_cast(time(nullptr)));
    int period_pos = input_file_name.find_last_of('.');
    if (period_pos == -1)
        output_file_name = output_file_name + time_as_string + ".txt";
    else
        output_file_name = output_file_name.replace(period_pos, output_file_name.length() - period_pos + 1, time_as_string + ".txt");
    ofstream fout;
    fout.open(output_file_name);
    assert(fout.good());

    cout < word_counter=""><>
    const int word_counts_fwidth = static_cast(log10(max_word_count)) + 1;
    const int line_number_fwidth = static_cast(log10(line_number)) + 1;
    const int words_per_line = 36;
    //using new variable for reference
 int newindex = 0;
    for (int idx = 0; idx < all_words.size();="">
    {
        fout < setw(max_word_length)="">< left="">< all_words[idx]="">< '="" '="">< right="">< setw(word_counts_fwidth)="">< right="">< all_word_counts[idx]=""><>
        //for (int idx2 = 0; idx2 < all_line_numbers[idx].size();="">

  for (int idx2 = 0; idx2 < all_word_counts[idx];="">
        {
            if (idx2 != 0 && idx2 % words_per_line == 0)
                fout <>
            fout < setw(line_number_fwidth)="">< right="">< ++newindex="">< '="">
        }
        fout <>
        fout <>
    }
    fout.close();
    system("pause");
    return 0;
}
int findWord(const vector& words, const string& word)
{
    for (int idx = 0; idx < words.size();="">
        if (words[idx] == word)
            return idx;
    return -1;
}
vector getWords(const string& text)
{
    vector words;
    int start_pos = 0;
    while (start_pos <>
    {
        while (start_pos < text.length()="" &&="">
            start_pos++;
        string word = empty_string;
        while (start_pos < text.length()="" &&="">
        {
            word += static_cast(toupper(text[start_pos]));
            start_pos++;
        }
        if (word.length() > 0)
            words.push_back(word);
    }
    return words;

}