Loading... , Или так #include <iostream> int first_k_of_n(int n, int k) { if (k <= 0) return -1; int temp = 0, res = 0, pow10 = 0; n = abs(n); while (n > 0) { temp = temp * 10 + n % 10; n /= 10; ++pow10; } if (k > pow10) k = pow10; for (int i = 0; i < k; ++i) { res = res * 10 + temp % 10; temp /= 10; } return res; }