Magic squares. An n × n matrix that is filled with the numbers 1, 2, 3, . . ., n2 is a magic square if the sum of the elements in each row, in each column, and in the two diagonals is the same value. Write a program that reads in 16 values from the keyboard and tests whether they form a magic square when put into a 4 × 4 array. You need to test two features:

1. Does each of the numbers 1, 2, ..., 16 occur in the user input?
2. When the numbers are put into a square, are the sums of the rows, columns, and diagonals equal to each other?

16 3 2 13 5 10 11 8 9 6 7 12 4 15 14 1