#include <iostream>
#include <cstdlib>
using namespace std;

void f00();   void f01();   void f02();
void f10();   void f11();   void f12();

int main()
{
	const size_t xmax = 3;

	void (*const a[][xmax])() = {
		{f00, f01, f02},   //or &f00 with explicit "address of" operator
		{f10, f11, f12}
	};
	const size_t ymax = sizeof a / sizeof a[0];

	size_t x;   //uninitialized variable
	cin >> x;

	if (x >= xmax) {
		cerr << "x value " << x << " must be in the range 0 to "
			<< xmax - 1 << " inclusive\n";
			return EXIT_FAILURE;
	}

	size_t y;   //uninitialized variable
	cin >> y;

	if (y >= ymax) {
		cerr << "y value " << y << " must be in the range 0 to "
			<< ymax - 1 << " inclusive\n";
			return EXIT_FAILURE;
	}

	a[y][x]();   //or (*a[y][x])() with explicit dereferencing operator
	return EXIT_SUCCESS;
}