Mr. Dobos: N-GRAMS

main.cpp

#include <iostream>
#include <fstream>
#include <string>
#include <unordered_map>

using namespace std;

void ljust(string &str, const size_t num, const char pch = 'X') {
    if(num > str.size())
        str.insert(str.size(), num - str.size(), pch);
}

int main () {
    string word;
    int g_count;
    bool read; // the "read" state switch
    char c; // current symbol
    int m; // choice
    bool fromfile; // input method
    string ifp; // input file path
    ifstream fin; // input file

    // I Choose method of input
    cout << "Do I need to read from file? (y/N)";
    cin >> c;
    fromfile = (c == 'y' || c == 'Y') ? true : false;

    // II Input
    if (fromfile) {
        cout << "Enter file path\n";
        cin >> ifp;
        fin.open(ifp);
        if (!fin.is_open())
            cout<<"Error opening file\n";
        else {
            word = "";
            g_count = 0;
            read = false;
            do { c = fin.get();
                if ((c != ' ')&&(c != EOF)) {
                    read = true;
                    if (isalpha(c))
                        word.insert(word.size(), 1, c);
                    else
                        g_count = (g_count * 10) + (c - '0');
                } else if (read) {
                    read = false;
                }
            } while (c != EOF);
        }
    } else {
        cout << "Input word: ";
        cin >> word;
        cout << "Input # of grams: ";
        cin >> g_count;
    }

    // III Process & Output
    for (int i = 1; i <= g_count; i++) {
        unordered_map<string,int> grams;
        cout << i << "-GRAM:";
        for (int j = 0; j < word.length(); j+=i)
        {
            string current = word.substr(j, i);
            if (current.length() < i)
                ljust(current, i);
            grams[current]++;
            cout << current << ' ';
        }
        for (auto it : grams)
            std::cout << " " << it.first << ":" << it.second;
        cout << endl;
    }
    return 0;
}