/** * Magic Square Generator * * @author tnt2ultra * 2019-05-10 */ import java.util.Arrays; import java.util.Scanner; // ------------------------------------- // Input one number - square side length // ------------------------------------- public class Program { static int[][] matrix; public static void main(String[] args) { System.out.println("Magic Square Generator"); Scanner sc = new Scanner(System.in); boolean bad = false; do { System.out.print("Enter number of cells on each side of magic square (0 - exit): "); int n = sc.nextInt(); System.out.println(n); if (n < 0 || n == 2) { System.out.printf("Magic square with side = %d does not exists\n", n); continue; } matrix = new int[n][n]; if (n % 2 != 0) { generateOdd(n); } else { int z = 1; for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { matrix[i][j] = z++; } } if (n % 4 == 0) { generateEven4(n); } else { generateEven2(n); } } bad = printSquare(matrix); checkSquare(matrix, bad); } while (false /* !bad */ ); } public static void generateOdd(int n) { for (int y = 0; y < n; y++) { for (int x = 0; x < n; x++) { int y1 = (((n + 1) / 2 + y + x) % n); int x1 = (((n + 1) / 2 + y + n - x - 1) % n) + 1; matrix[y][x] = (y1 * n) + x1; } } } public static void generateEven4(int n) { int j = 2; int m = n / 2; for (int i = 1; i <= m; i++) { for (int k = 1; k <= m / 2; k++) { if (j == m + 1) { j = 2; } else if (j == m + 2) { j = 1; } int s = n - i + 1; int b = n - j + 1; int temp = matrix[i - 1][j - 1]; matrix[i - 1][j - 1] = matrix[s - 1][b - 1]; matrix[s - 1][b - 1] = temp; temp = matrix[i - 1][b - 1]; matrix[i - 1][b - 1] = matrix[s - 1][j - 1]; matrix[s - 1][j - 1] = temp; j += 2; } } } public static void generateEven2(int n) { int m = n / 2; int r = (m - 1) / 2; for (int i = 1; i <= m; i++) { int j = i; for (int k = 1; k <= r; k++) { if (j > m) { j = 1; } int s = n - i + 1; int b = n - j + 1; int temp = matrix[i - 1][j - 1]; matrix[i - 1][j - 1] = matrix[s - 1][b - 1]; matrix[s - 1][b - 1] = temp; temp = matrix[i - 1][b - 1]; matrix[i - 1][b - 1] = matrix[s - 1][j - 1]; matrix[s - 1][j - 1] = temp; j++; } } int i = 1; int j = r + 1; for (int k = 1; k <= m; k++) { if (j > m) { j = 1; } int s = n - i + 1; int temp = matrix[i - 1][j - 1]; matrix[i - 1][j - 1] = matrix[s - 1][j - 1]; matrix[s - 1][j - 1] = temp; i++; j++; } i = 1; j = r + 2; for (int k = 1; k <= m; k++) { if (j > m) { j = 1; } int b = n - j + 1; int temp = matrix[i - 1][j - 1]; matrix[i - 1][j - 1] = matrix[i - 1][b - 1]; matrix[i - 1][b - 1] = temp; i++; j++; } } static boolean printSquare(int[][] matrix) { boolean bad = false; System.out.println("Check Square:"); try { int maxMatrix = matrix[0][0]; for (int[] line : matrix) { int max = Arrays.stream(line).max().getAsInt(); if (max > maxMatrix) { maxMatrix = max; } } String start = "| "; String begin = "+-"; int maxLen = ("" + maxMatrix).length(); if (maxLen > 1) { maxLen++; start = "|"; begin = "+"; } char[] arrChar = new char[(maxLen + 1) * matrix[0].length]; Arrays.fill(arrChar, '-'); String horLine = begin + new String(arrChar) + "+"; System.out.println(horLine); for (int[] line : matrix) { System.out.print(start); for (int n : line) { System.out.printf("%" + maxLen + "d ", n); } System.out.println("|"); } System.out.println(horLine); } catch (Exception e) { bad = true; } return bad; } static void checkSquare(int[][] matrix, boolean bad) { int sum = 0; int sumD1 = 0; int sumD2 = 0; int len = 0; boolean isValid = !bad; try { len = matrix.length; for (int y = 0; y < len; y++) { int sumX = 0; int sumY = 0; sumD1 += matrix[y][y]; sumD2 += matrix[len - y - 1][y]; for (int x = 0; x < matrix[y].length; x++) { sumX += matrix[y][x]; sumY += matrix[x][y]; } if (y == 0) { sum = sumX; } isValid &= sum == sumX && sum == sumY; } isValid &= sum == sumD1 && sum == sumD2; } catch (Exception e) { isValid = false; bad = true; } if (isValid) { System.out.printf("This is VALID magic square %d*%d with sum = %d\n", len, len, sum); } else { if (bad) { System.out.print("Invalid matrix: "); if (matrix == null) { System.out.println("null"); } else { System.out.println("Not enough data or matrix is not square"); } } else { System.out.println("*** Invalid: square matrix is not magic ***"); } } System.out.println(""); } }