laba_2_4_c++

#include <iostream>
#include <fstream>
using namespace std;
ifstream fin;
ofstream fout;

int choose() {
    int chose;
    bool isIncorrect;
    do{
        cin >> chose;
        isIncorrect = false;
        if (cin.fail() || !(chose == 1 || chose == 0)){
            isIncorrect = true;
            cout << "Please, choose." << endl << "1 is console input/output, 0 is file input/output." << endl;
            cin.clear();
            while (cin.get() != '\n');
        }
    } while (isIncorrect);
    return chose;
}

// консольный ввод и вывод

int inputData() {
    int n = 0;
    bool isIncorrect;;
    do {
        cin >> n;
        isIncorrect = false;
        if (cin.fail()) {
            cout << "Please, enter a positive integer number:" << endl;
            isIncorrect = true;
            cin.clear();
            while (cin.get() != '\n');
        }
    } while (isIncorrect);
    return n;
}

int inputPositiveNumber() {
    int npos;
    const int MIN = 1;
    bool isIncorrect;
    do {
        npos = inputData();
        isIncorrect = false;
        if (npos < MIN) {
            cout << "Please, enter a positive number." << endl;;
            isIncorrect = true;
        }
    } while (isIncorrect);
    return npos;
}


int inputArraySize() {
    bool isIncorrect;
    int num = 0;
    do {
        num = inputData();
        isIncorrect = false;
        if (num % 2 != 0) {
            cout << "Please, enter an even number:" << endl;
            isIncorrect = true;
            cin.clear();
            while (cin.get() != '\n');
        }
    } while (isIncorrect);
    return num;
}
int** inputArray(int num) {
    int i = 0;
    int j = 0;
    int** arr = new int* [num];
    for (i = 0; i < num; i++)
        arr[i] = new int[num];
    for (i = 0; i < num; i++)
        for (j = 0; j < num; j++)
            arr[i][j] = inputData();
    return arr;
}

int* transferMatrixtoVector(int n, int** arr, int starti, int startj) {
    const int MIN = 4;
    int* quarter = new int[(n * n) / MIN];
    int k = 0;
    int i = 0;
    int j = 0;
    int halfn = n / 2;
    for (i = starti; i < starti + halfn; i++) {
        for (j = startj; j < startj + halfn; j++) {
            quarter[k] = arr[i][j];
            k++;
        }
    }
    return quarter;
}

void outputArray(int num, int** arr) {
    int i = 0;
    int j = 0;
        for (i = 0; i < num; i++) {
            for (j = 0; j < num; j++)
                cout << arr[i][j] << ' ';
            cout << '\n';
        }
}

//functions for files:

string inputFilePath() {
    const int EXTENSION_SIZE = 4;
    string path;
    string ext;
    bool isIncorrect;
    do {
        isIncorrect = false;
        cout << "Input path to file: " << endl;
        cin >> path;
        fin.open(path);
        if (path.size() > EXTENSION_SIZE) {
            ext = path.substr(path.size() - EXTENSION_SIZE, EXTENSION_SIZE);
        }
        else {
            cout << "Incorrect file name." << endl;
            isIncorrect = true;
        } if (!isIncorrect && ext != ".txt") {
            cout << "Must have .txt!" << endl;
            isIncorrect = true;
        }
        else if (!isIncorrect && !fin.is_open()) {
            cout << "Wrong way to file." << endl;
            isIncorrect = true;
        }
    } while (isIncorrect);
    fin.close();
    return path;
}




int inputSizeOfMatrixFromFile(string path) {
    int n;
    bool isIncorrect;
    const int MIN = 1;
    const int MAX = 10;
    do
    {
        isIncorrect = false;
        fin.open(path);
        fin >> n;
        if (n < MIN || n > MAX) {
            isIncorrect = true;
            cout << "Incorrect matrix size. Your matrix size must be from " << MIN << " to " << MAX << "." << endl;
            path = inputFilePath();
        }
    } while (isIncorrect);
    return n;
}

int** inputMatrixFile(string path, int num)
{
    ifstream fileIn(path);
    bool isIncorrect = false;
    int** arr;
    arr = new int* [num];
    for (int i = 0; i < num; i++)
        arr[i] = new int[num];
    for (int i = 0; (i < num) && (!isIncorrect); i++) {
        for (int j = 0; (j < num) && (!isIncorrect); j++) {
            do
            {
                isIncorrect = false;
                try {
                    fin >> arr[i][j];
                }
                catch (fstream::failure& e) {
                    cout << "Mistake of reading from file. Code of mistake " << e.code() << "\n";
                    isIncorrect = true;
                }
            } while (isIncorrect);
        }
    }
    return arr;
}

void fileOutput(int n, int** arr) {
    cout << "Input second file path for writing data there:" << endl;
    string path = inputFilePath();
    fout.open(path);
    int prod;
    for (int i = 0; i < n; i++)
    {
        prod = 1;
        for (int j = 0; j < n; j++)
        {
            prod *= arr[i][j];
        }
        if (prod != 0)
        {
            for (int j = 0; j < n; j++)
            {
                fout << arr[i][j] << ' ';
            }
            fout << '\n';
        }
    }
    cout << "Successful output in file." << endl;
    fout.close();
}

int main() {
    int n = 0;
    int** arr;
    cout << "Enter 1 or 0. " << endl << "1 is console input, 0 is file input." << endl;
    int chose = choose();
    if (chose == 1) {
        cout << "Input number of digits : " << endl;
        n = inputArraySize();
        cout << "Enter the numbers one by one: " << endl;
        arr = inputArray(n);
    }
    else {
        string str = inputFilePath();
        n = inputSizeOfMatrixFromFile(str);
        arr = inputMatrixFile(str, n);
    }


    int starti = 0;
    int startj = starti;
    int* bufferFor1 = transferMatrixtoVector(n, arr, starti, startj);

    starti = 0;
    startj = n / 2;;
    int* bufferFor2 = transferMatrixtoVector(n, arr, starti, startj);

    starti = n / 2;
    startj = 0;
    int* bufferFor3 = transferMatrixtoVector(n, arr, starti, startj);

    starti = n / 2;
    startj = starti;
    int* bufferFor4 = transferMatrixtoVector(n, arr, starti, startj);

    int i = 0;
    int j = 0;
    int k = 0;
    int l = 0;
    for (i = 0; i < n; i++) {
        for (j = 0; j < n; j++) {
            if ((i < n / 2) && (j < n / 2)) {
                arr[i][j] = bufferFor4[k];
            }
            k = 0;
            if ((i < n / 2) && (j > n / 2 - 1)) {
                arr[i][j] = bufferFor3[k];
            }
            k = 0;
            if ((i > n / 2 - 1) && (j < n / 2)) {
                arr[i][j] = bufferFor1[k];
            }
            k = 0;
            if ((i > n / 2 - 1) && (j > n / 2 - 1)) {
                arr[i][j] = bufferFor2[k];
                k++;
            }
        }
    }
    cout << "Enter 1 or 0. " << endl << "1 is console output, 0 is file output." << endl;
    chose = choose();
    if (chose == 1) {
        outputArray(n, arr);
    }
    else {
        fileOutput(n, arr);
    }
    for (i = 0; i < n; i++)
        delete[] arr[i];
    return 0;
}