Graduri graf orientat prin matricea varfuri-arce

#include <fstream>
using namespace std;

ifstream fin("date.in");
ofstream fout("date.out");

int grad_ext[100], grad_int[100];

int main()
{
    int n, m, i, j, a[100][100];
    fin >> n >> m;
    for(i = 1; i <= n; i++)
        for(j = 1; j <= m; j++)
            fin >> a[i][j];
    for(j = 1; j <= m; j++)
        for(i = 1; i <= n; i++)
        {
            if(a[i][j] == 1)
                grad_ext[j]++;
            if(a[i][j] == -1)
                grad_int[j]++;
        }
    for(i = 1; i <= n; i++) {
        fout << "Gradul intern al varfului " << i << " este: " << grad_int[i];
        fout << "\nGradul extern al varfului " << i << " este: " << grad_ext[i] << "\n\n";
    }
    fin.close();
    fout.close();
    return 0;
}