Step 6 of 6
2D arrays
A 2D array is an array of rows:
int grid[2][3] = {
{1, 2, 3},
{4, 5, 6},
};
printf("%d\n", grid[1][2]); // row 1, column 2: 6
Loop over it with nested loops: rows outside, columns inside.
Your turn: read a 3x3 grid of numbers and print the sum of each row on its own line, then the sum of the main diagonal (top-left to bottom-right) as diag N.