Read a rows x cols grid of integers (already read into grid for you), and print the sum of each row, one sum
per line.
This is the standard “visit every element of a 2D array” nested loop from the lesson, with one twist: the sum has
to reset at the start of every row, not accumulate across the whole grid. Declare sum fresh inside the outer
loop, not before it – if you declare it once outside both loops, you’ll get one running total for the entire grid
instead of one total per row.