main.cpp

#include <bits/stdc++.h>
#include <filesystem>
using namespace std;
namespace fs = std::filesystem;

int main()
{
    unordered_map<string, vector<string>> index; // word -> list of files
    string folder = "data";                      // folder containing text files

    // Step 1: Read all .txt files in folder
    for (const auto &entry : fs::directory_iterator(folder))
    {
        if (entry.path().extension() == ".txt")
        {
            string filename = entry.path().filename().string();
            ifstream file(entry.path());
            string word;
            while (file >> word)
            {
                // clean punctuation and make lowercase
                word.erase(remove_if(word.begin(), word.end(), ::ispunct), word.end());
                transform(word.begin(), word.end(), word.begin(), ::tolower);
                index[word].push_back(filename);
            }
            file.close();
        }
    }

    // Step 2: Remove duplicates in the word->file list
    for (auto &pair : index)
    {
        sort(pair.second.begin(), pair.second.end());
        pair.second.erase(unique(pair.second.begin(), pair.second.end()), pair.second.end());
    }

    cout << "✅ Indexed all text files in folder '" << folder << "'\n";

    // Step 3: Search loop
    string query;
    while (true)
    {
        cout << "\nEnter a word to search (or 'exit' to quit): ";
        cin >> query;
        transform(query.begin(), query.end(), query.begin(), ::tolower);
        if (query == "exit")
            break;

        if (index.find(query) != index.end())
        {
            cout << "🔍 Found in files:\n";
            for (auto &f : index[query])
                cout << " - " << f << "\n";
        }
        else
        {
            cout << "❌ No match found.\n";
        }
    }

    return 0;
}