Tổ hợp

#include <iostream>

using namespace std;

void print(int a[], int n) {
    cout << endl;
    for (int i = 1; i <= n; ++i)
        cout << a[i] << " ";
}
int main()
{
    int n, k;
    int a[100];

    cout << "n = "; cin >> n;
    cout << "k = "; cin >> k;

    for (int i = 1; i <= k; ++i) a[i] = i;

    int i;
    do {
        print(a, k);
        i = k;
        while (i > 0 && a[i] == n - k + i) --i;
        if (i > 0) {
            ++a[i];
            for (int j = i + 1; j <= k; ++j) a[j] = a[j - 1] + 1;
        }
    } while (i > 0);
}