Question: vector flatten(int a[100][200]);
Part 1: Write a function named flattens that takes a two-dimensional array of integers with 100 rows and 200 columns and returns a vector that contains all of the array's elements.
Copy the values a row at a time. In other words, first copy row 0 into the vector, then row 1, then row 2, and so on. The declaration of flatten is give above.