A square matrix has the same number of rows and columns. The diagonal of a square matrix is made up of the entries which run from the upper left corner to the lower right corner. In the previous problem, the diagonal is made up of those entries which are equal to 1. A square matrix is upper triangular if all entries below the diagonal are 0. The diagonal entries and the entries above the diagonal can have any value, including 0, but all entries below the diagonal must have the value 0. Write a function called isUpper which has parm: an array with N rows and N columns. The function should return true if the array represents an upper triangular matrix, and return false otherwise.