Почему идентификаторы i,j,k не определены, когда пишу mas[k] matr[i][j] c++

int vvod(int n, int matr, FILE* f, int m, int mas)
{

    FILE* f;
    f = fopen("dat.txt", "rt");
    fscanf_s(f, "%d", &n);
    int** matr = new int* [n];
    for (int i = 0; i < n; i++);
    {matr[i] = new int[n];
    }
    for (int i = 0; i < n; i++);
    for (int j = 0; j < n; j++);
    fscanf_s(f, "%d", &matr[i][j]);
    fscanf_s(f, "%d", &m);
    int** mas = new int* [m];
    for (int k = 0; k < m; k++);
    {mas[k] = new int[k];
    }
    for (int k = 0; k < m; k++);
    fscanf_s(f, "%d", &mas[k]);
    return 0;

}