Thread: RND exercise

Hello ,

I would like share this beginner code in order to get any advises.
( if you have time , thanks)

Description:
Choose a level. Level number determines the maximum numbers of words to turn into an hidden word
Every hidden word is overwrote by "_" char and identified by a progressive number
You have to choice a number and guess what words is back before to press enter

Example:
original text : Students compile a collection of their texts in a variety of genres

<<Difficulty level 1-10 ( 1 = harder): ? 5>>

Students 1______ a collection of 2____ texts 3__ a variety 4__ genres

<<What number you choose ? 2>>
speak loudly what word you have guessed..

Here is : their

<<What number you choose ? >>
and so on...

Code:

#include "pch.h"
#include <iostream>
#include <string>
#include <sstream>
#include <vector>
#include <stdio.h>
#include <set>
#include <ctime> 
#include <random>


using namespace std;


vector <wstring> countWords(wstring text);
vector<int> mersenne(int seed, int start, int end, size_t howManyNumb);
vector<wstring> quizIt(vector <wstring> words, vector <int> rnd);

const unsigned int seed = time(0);

int main()
{
    wstring text( // Odissey
        L"Narrami, o musa , l'uomo dall'agile mente che a lungo andó vagando, "
        "poi che cadde troia ,la forte città e di molte genti vide le terre "
        "e così conobbe la natura dell'anima, molti dolori patì nel suo cuore "
        " lungo le vie del mare lottando per tornare in patria coi compagni. "
        " Ma per loro follià (come simili a fanciulli !) non li potè sottrarre "
        " alla morte. Poi che mangiarono i buoi del sole , figlio del cielo , "
        " tolse loro il tempo di ritorno. Questo narrami,o dea , figlia di Zeus "
        " e comincia di dove tu vuoi ");
    
    vector <wstring> quiz;
    vector <wstring> Words;
    vector <int> rnd;


    size_t level = 1;
    int difficulty = 1;
    
    cout << "Difficulty level 1-10 ( 1 = harder):> ";
    cin >> difficulty;

    Words = countWords(text);
    level = (Words.size() / difficulty)-1;
    cout << level << " " << Words.size();


    rnd = mersenne(seed, 1, Words.size() - 1, level);
    quiz = quizIt(Words,rnd);

    int wordNumber = 0;
    while (1) {
        cout << "Completa numero:> "  ;
        cin >> wordNumber;
        wcout <<  quiz.at(wordNumber) << endl;
    }// ctrl-c to exit


    return 0;
}
vector <wstring> countWords(wstring text) {


    wstring wordExtracted;
    vector <wstring> words;

    wistringstream iss(text);
    while (iss >> wordExtracted) { words.push_back(wordExtracted); }


    return words;
}
vector<wstring> quizIt(vector <wstring> words, vector <int> rnd) {
    
    vector <wstring> hiddenWords;
    vector <wstring>::iterator itP;
    vector <int>::iterator it;
    int newLine = 0;
    int contator=0;
    
    std::cout << "Hello World!\n";


    for (it = rnd.begin(); it < rnd.end(); it++) {


        hiddenWords.push_back(words[*it]);    // saves the hidden words choices by random numb generator 
        // overwrites the hiddenwords by '_' char and add an id number
        words.at(*it) = to_wstring(contator++) + wstring(words[*it].size(), '_');
    }
    
    setlocale(LC_ALL, ".437");
    for (itP = words.begin(); itP < words.end(); itP++) {

        if (!(newLine = (newLine + 1) % 12)) cout << endl;
        wcout << *itP << ' ';
    }
    cout << endl;
    return hiddenWords;
}
vector<int> mersenne(int seed, int start, int end, size_t howManyNumb) {


    set<int> numb;
    vector<int> result;
    int rnd = 0;

    mt19937_64 rndGen(seed);
    uniform_int_distribution<int> rndDist(1, end);
    
    while (numb.size() < howManyNumb) { 
        
        rnd = rndDist(rndGen);

        if (numb.insert(rnd).second) { // If doesn't fail ,saves rnd to result
            result.push_back(rnd);
        }
    }
    return result;
}

Originally Posted by laserlight

My advice would be:

• Use nullptr, not 0, when you need a null pointer constant.

Done

Originally Posted by laserlight

You shouldn't default to passing containers like vector (or wstring, which technically isn't a container but has similiar expensive copying semantics) by value. The use of move semantics aside, if you don't need a copy of the container and won't modify the container, then pass by const reference, otherwise pass by non-const reference. For a more comprehensive and advanced overview: Parameter passing: Prefer simple and conventional ways of passing information

I've got to study it , but I tried to do something
You're right , passing by value it doesn't make sense

Code:

vector <wstring> countWords(const wstring &text) {
    
    wstring wordExtracted;
    vector <wstring> words;
    wistringstream iss(text);
    while (iss >> wordExtracted) { words.push_back(wordExtracted); }
    return words;
}
vector<wstring> quizIt(vector <wstring> &words, vector <int> &rnd) {
    
    vector <wstring> hiddenWords;
    std::cout << "Hello World!\n";
    int contator = 0;
    for (auto it = rnd.begin(); it < rnd.end(); it++) {
        hiddenWords.push_back(words[*it]);    // saves the hidden words choices by random numb generator 
        // overwrites the hiddenwords by '_' char and add an id number
        words.at(*it) = to_wstring(contator++) + wstring(words[*it].size(), '_');
    }
    setlocale(LC_ALL, ".437");
    int newLine = 0;
    for (auto itP = words.begin(); itP < words.end(); itP++) {
        // Prints the quiz
        if (!(newLine = (newLine + 1) % 12)) cout << endl;
        wcout << *itP << ' ';
    }
    cout << endl;
    return hiddenWords;
}

Thanks Light