How to write a vector to a file with a function in C++?

Question

Here are a few snippets of my code. First are my functions that I wrote. The one giving me an error is the fileout function, which is supposed to write the vector to a file.

vector<int> random(int rowsize, int columnsize) // generates a random matrix given number of rows and columns, stores it as a 1-dimensional vector
{
    int elements = rowsize*columnsize;
    vector<int> x(elements);
    int matrix[10][10];

    int n=0;
    for(int i = 0; i < rowsize; i++)
            {
                for(int j = 0; j < columnsize; j++)
                {
                    matrix[i][j]= -10 + rand() % 21;
                    x[n++] = matrix[i][j];
                }
            }

    return x;
}

void print(vector<int> matrix, int columnsize) //prints the matrix given the number of columns
{
    for(int i=0; i < matrix.size(); i++)
    {
        if(i%columnsize != 0)
            cout << setw(10) << matrix[i];
        if(i%columnsize == 0)
            cout << endl << setw(10) << matrix[i];
    }
    cout << endl;
}

vector<int> addmat(vector<int> matrixA, vector <int> matrixB) //adds two matrices together, takes vector input
{
    vector<int> matrix(matrixA.size());
    for(int i=0; i< matrixA.size(); i++)
        matrix[i] = (matrixA[i] + matrixB[i]);

    return matrix;
}

vector<int> filefill(ifstream &fin, string file, int rowsize, int columnsize) //creates a matrix from a file
{
    fin.open(file.c_str());
    vector<int> matrix;
    int number;

    for(int i=0; i < rowsize*columnsize; i++)
    {
        while(fin >> number)
            matrix.push_back(number);
    }

    fin.close();
    return matrix;
}

void fileout(ofstream fout, string file, vector<int> matrix) //writes a matrix onto a file
{
    fout.open(file.c_str());
    for(int i=0; i < matrix.size(); i++)
        fout << matrix[i];
    fout.close();
}

This is the use of the function in the main. The fout inside the fileout function is marked as an error:

"6 IntelliSense: "std::basic_ofstream<_Elem, _Traits>::basic_ofstream(const std::basic_ofstream<_Elem, _Traits>::_Myt &_Right) [with _Elem=char, _Traits=std::char_traits]" (declared at line 1034 of "C:\\Program Files (x86)\\Microsoft Visual Studio 11.0\\VC\\include\\fstream") is inaccessible c:\\Users\\William\\Desktop\\C++\\Homework8\\HW8\\hw8.cpp 163 11 HW8

else if (answer == "N" || answer == "n")
    {

        matrixA = random (Arow, Acolumn);
        cout << "Matrix A" << endl;
        print(matrixA, Acolumn);

        matrixB = random (Brow, Bcolumn);
        cout << "Matrix B" << endl;
        print(matrixB, Bcolumn);

        cout << endl << "Matrix A + Matrix B =" << endl;

        vector<int> matrixC = addmat (matrixA, matrixB);
        print(matrixC, Acolumn);

        for (int i = 0; i < matrixA.size(); i++)
        {
            matrixB.push_back(matrixA[i]);
        }

        string filo;
        cin >> filo;
        ofstream fout;
        fileout(fout, filo, matrixB);


    }

Not sure what the problem is????????????

Answer 1

Instead of accepting an ofstream object from whoever calls the fileout function, try creating a local ofstream fout inside of fileout :

void fileout(string file, vector<int> matrix) //writes a matrix onto a file
{
    ofstream fout;
    fout.open(file.c_str());
    for(int i=0; i < matrix.size(); i++)
        fout << matrix[i];
    fout.close();
}