Your code is trying to output an array of seats, but you are using the << operator to output the entire array, not its elements. Instead, you must use the indexes i and j to access individual array elements.
Here is the corrected code:
#include <iostream>
using namespace std;
int main (){
int seats[2][3] = {
{1, 2, 3},
{4, 5, 6}
};
for (int i = 0; i < 2; i++)
{
for (int j = 0; j < 3; j++)
{
cout << seats[i][j] << endl;
}
}
}