lab3_2(C++)

#include <iostream>
#include <fstream>
#include <set>
#include <string>
#include <algorithm>

using namespace std;

const set <char> setOfDigitsAndOperations { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '-', '*', '/', ':', '^'};

char takeSource() {
    char choice;
    cin >> choice;
    while ((choice != '1') && (choice != '2')) {
        while (cin.get() != '\n') {
            cin.clear();
        }
        cout << "Incorrect input!!!\nSelect the source:\n1:Console\n2:File\nEnter 1 or 2: ";
        cin >> choice;
    }
    return choice;
}

string takeInPath() {
    string path;
    bool isIncorrect;
    cout << "Enter file path: ";
    do {
        isIncorrect = true;
        cin >> path;
        ifstream fin(path);
        if (fin.is_open()) {
            isIncorrect = false;
            fin.close();
        }
        else {
            cout << "File is not found\nEnter file path: ";
        }
        if (!isIncorrect && ((path.length() < 4) || (!(path.substr(path.length() - 4) == ".txt")))) {
            cout << "File is found, but it is not \".txt\" type file\nEnter file path : ";
            isIncorrect = true;
        }
    } while (isIncorrect);
    return path;
}

string takeOutPath() {
    string path;
    bool isIncorrect;
    cout << "Enter file path: ";
    do {
        isIncorrect = false;
        cin >> path;
        if ((path.length() < 4) || (!(path.substr(path.length() - 4) == ".txt"))) {
            cout << "It should be a \".txt\" file\nEnter file path: ";
            isIncorrect = true;
        }
    } while (isIncorrect);
    return path;
}

int takeSize() {
    const int MIN_SIZE = 2;
    const int MAX_SIZE = 30;
    int number = 0;
    bool isIncorrect;
    do {
        isIncorrect = false;
        cin >> number;
        if (!cin.good()) {
            isIncorrect = true;
            cout << "Incorrect input!!!\n";
            while (cin.get() != '\n') {
                cin.clear();
            }
        }
        if ((!isIncorrect) && (number < MIN_SIZE || number > MAX_SIZE)) {
            isIncorrect = true;
            cout << "Incorrect input!!!\n";
        }
    } while (isIncorrect);
    return number;
}

char takeChar() {
    char inputChar;
    bool isIncorrect;
    string line;
    do {
        cin >> line;
        isIncorrect = false;
        if ((line.length() != 1)) {
            cout << "Incorrect input!!! Must be char:";
            isIncorrect = true;
        }
        else {
                inputChar = line[0];
        }
    } while (isIncorrect);
    return inputChar;
}

set <char> takeSetFromConsole() {
    cout << "Enter size: ";
    int size = takeSize();
    set <char> inputSet;
    for (int i = 0; i < size; i++) {
        cout << "Enter element " << (i + 1) << ": ";
        inputSet.insert(takeChar());
    }
    return inputSet;
}

set <char> takeSetFromFile(const string path)  {
    ifstream fin(path);
    set <char> inputSet;
    string sign;
    bool isCorrect = true;
    while (isCorrect && !fin.eof()) {
        fin >> sign;
        if (sign.size() == 1) {
            inputSet.insert(sign[0]);
        }
        else {
            cout << "Incorrect file data\n";
            isCorrect = false;
        }
    }
    fin.close();
    if (!isCorrect) {
        cout << "Enter set from console:\n";
        inputSet = takeSetFromConsole();
    }
    return inputSet;
}

set <char> takeSet(const char source) {
    string inPath;
    set <char> inputSet;
    if (source == '1') {
        inputSet = takeSetFromConsole();
    }
    else {
        inPath = takeInPath();
        inputSet = takeSetFromFile(inPath);
        }
    return inputSet;
}

set <char> findAnswer(set <char> inputSet) {
    set <char> answer;
    set_intersection(inputSet.begin(), inputSet.end(), setOfDigitsAndOperations.begin(), setOfDigitsAndOperations.end(), inserter(answer, answer.end()));


    return answer;
}

void outputToConsole(set <char> setOfAnswers) {
    cout << "Answer is:\n(";
    set<char>::iterator number;
    for (number = setOfAnswers.begin(); number != setOfAnswers.end(); number++) {
        cout << " " << *number;
    }
    cout << ")";
}

void outputToFile(const string path, set <char> setOfAnswers) {
    ofstream fout;
    fout.open(path);
    fout << "Answer is:\n(";
    set<char>::iterator number;
    for (number = setOfAnswers.begin(); number != setOfAnswers.end(); number++) {
        fout << " " << *number;
    }
    fout << ")";
    fout.close();
    cout << "Done";
}

void output(const char source, set <char> setOfAnswers) {
    string outPath;
    if (source == '1') {
        outputToConsole(setOfAnswers);
    }
    else {
        outPath = takeOutPath();
        outputToFile(outPath, setOfAnswers);
    }
}

int main() {
    cout << "Welcome to the program that will print a set, whose elements are signs of arithmetic operations and digits from a given set\nSelect the source for entering the sentence:\n1:Console\n2:File\nEnter 1 or 2: ";
    char inputSource = takeSource();
    set <char> inputSet = takeSet(inputSource);;
    set <char> answer = findAnswer(inputSet);
    cout << "Select the source for output:\n1:Console\n2:File\nEnter 1 or 2: ";
    char outputSource = takeSource();
    output(outputSource, answer);
}