Minimul de pe coloane (matrice)

#include <iostream>
using namespace std;
int main()
{
    int i, j, m, n, a[100][100], b[100], min;
    cout << "Introduceti numarul de linii: ";
    cin >> n;
    cout << "Introduceti numarul de coloane: ";
    cin >> m;
    for(i = 1; i <= n; i++)
        for(j = 1; j <= m; j++)
        {
            cout << "a[" << i << "][" << j << "]=";
            cin >> a[i][j];
        }
    for(j = 1; j <= m; j++)
    {
        min = a[1][j];
        for(i = 2; i <= n; i++)
            if(a[i][j] < min)
                min = a[i][j];
            b[j] = min;
    }
    cout << endl;
    for(i = 1; i <= n; i++) {
        for(j = 1; j <= m; j++)
            cout << a[i][j] << " ";
        cout << endl;
    }
    cout << endl;
    for(j = 1; j <= n; j++)
        cout << b[j] << " ";
    return 0;
}