Problem
Design and write a program that reads a 4x4 array of integers from the keyboard and determines whether or not these form a magic square. A magic square is a matrix of numbers in which the sum of each row and the sum of each column are identical. Optional: Add the criterion that the sum of the two diagonals of the square must be the same as the sum of every row and the sum of every column in the matrix for it to be a magic square.