java语言程序设计1-10章课后答案（代码）

import java.util.Scanner; public class Exercise08_14 { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.print("Enter the length of a square matrix: "); int n = input.nextInt(); int[][] board = new int[n][n]; boolean isSameOnARow = false, isSameOnAColumn = false, isSameOnADiagonal = false, isSameOnASubdiagonal = false; for (int i = 0; i < board.length; i++) { for (int j = 0; j < board[0].length; j++) { board[i][j] = (int) (Math.random() * 2); System.out.print(board[i][j]); } System.out.println(); } // Check rows for (int i = 0; i < board.length; i++) { boolean same = true; for (int j = 1; j < board[0].length; j++) { if (board[i][0] != board[i][j]) { same = false; break; } } if (same) { System.out.println("All " + board[i][0] + "'s on row " + i); isSameOnARow = true; } } // Check columns for (int j = 0; j < board[0].length; j++) { boolean same = true; for (int i = 1; i < board.length; i++) { if (board[0][j] != board[i][j]) { same = false; break; } } if (same) { System.out.println("All " + board[0][j] + "'s on column " + j); isSameOnAColumn = true; } } // Check major diagonal boolean same = true; for (int i = 1; i < board.length; i++) { if (board[0][0] != board[i][i]) { same = false; break; } } if (same) { System.out.println("All " + board[0][0] + "'s on major diagonal"); isSameOnADiagonal = true; } // Check subdiagonal same = true; for (int i = 1; i < board.length; i++) { if (board[0][board.length - 1] != board[i][board.length - 1 - i]) { same = false; break; } } if (same) { System.out.println("All " + board[0][board.length - 1] + "'s on sub-diagonal"); isSameOnASubdiagonal = true; } if (!isSameOnARow) System.out.println("No same numbers on a row"); if (!isSameOnAColumn) System.out.println("No same numbers on a column"); if (!isSameOnADiagonal) System.out.println("No same numbers on the major diagonal"); if (!isSameOnASubdiagonal) System.out.println("No same numbers on the sub-diagonal"); } } // An alternative version without using break //import java.util.Scanner; // //public class Exercise08_14 { // public static void main(String[] args) { // Scanner input = new Scanner(System.in); // System.out.print("Enter the length of a square matrix: "); // int n = input.nextInt(); // // int[][] board = new int[n][n]; // boolean isSameOnARow = false, isSameOnAColumn = false, // isSameOnADiagonal = false, isSameOnASubdiagonal = false; // // for (int i = 0; i < board.length; i++) { // for (int j = 0; j < board[0].length; j++) { // board[i][j] = (int) (Math.random() * 2); // System.out.print(board[i][j]); // } // // System.out.println(); // } // // // Check rows // for (int i = 0; i < board.length; i++) { // boolean same = true; // for (int j = 1; j < board[0].length && same; j++) { // if (board[i][0] != board[i][j]) { // same = false; // } // } // if (same) { // System.out.println("All " + board[i][0] + "'s on row " + i); // isSameOnARow = true; // } // } // // // Check columns // for (int j = 0; j < board[0].length; j++) { // boolean same = true; // for (int i = 1; i < board.length && same; i++) { // if (board[0][j] != board[i][j]) { // same = false; // } // // } // if (same) { // System.out.println("All " + board[0][j] + "'s on column " + j); // isSameOnAColumn = true; // } // } // // // Check major diagonal // boolean same = true; // for (int i = 1; i < board.length && same; i++) { // if (board[0][0] != board[i][i]) { // same = false; // } // } // if (same) { // System.out.println("All " + board[0][0] + "'s on major diagonal"); // isSameOnADiagonal = true; // } // // // Check subdiagonal // same = true; // for (int i = 1; i < board.length && same; i++) { // if (board[0][board.length - 1] != board[i][board.length - 1 - i]) { // same = false; // } // } // if (same) { // System.out.println("All " + board[0][board.length - 1] + "'s on sub-diagonal"); // isSameOnASubdiagonal = true; // } // // if (!isSameOnARow) // System.out.println("No same numbers on a row"); // // if (!isSameOnAColumn) // System.out.println("No same numbers on a column"); // // if (!isSameOnADiagonal) // System.out.println("No same numbers on the major diagonal"); // // if (!isSameOnASubdiagonal) // System.out.println("No same numbers on the sub-diagonal"); // } //}