Заполнить матрицу элементами одномерного массива

#include <iostream>
#include <ctime>
#include <iomanip>

using namespace std;

const int N = 10;
const int M = 10;

void filling(int arr[N][M], int a, int b, int n, int m) {
	int arr_save[M];
	for (int i = 0; i < n; i++) {
		arr_save[i] = rand() % (b - a + 1) + a;
	}
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			arr[i][j] = arr_save[i];
		}
	}
}

int main() {
	srand(time(0));
	int array[N][M], n, m, a, b;
	while (true) {
		cout << "Write n and m" << endl;
		cin >> n >> m;
		if (n > N || m > M) {
			cout << "Number what you write is too high, n <= 10 and m <= 10, try again" << endl;
			continue;
		}
		else {
			break;
		}
	}
	while (true) {
		cout << "Write a and b to fill array " << endl;
		cin >> a >> b;
		if (a >= b) {
			cout << "a >= b, a need to be smaller than b, try again" << endl;
			continue;
		}
		else {
			break;
		}
	}
	filling(array, a, b, n, m);
	cout << endl << "n = " << n << " m = " << m << endl;
	cout << "Gap [" << a << ", " << b << "]" << endl;
	cout << "Matrix: " << endl;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < m; j++) {
			cout << setw(6) << array[i][j];
		}
		cout << "\n";
	}
}