如标题所示，我从 Eclipse 和 cmd 命令运行我的 Magic Square 程序时得到了不同的结果。 eclipse 没有意义。
(eclipse中“Wrong number...”这句话的位置应该是错的)
有人知道怎么解决吗？非常感谢!
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;
public class MagicSquare{
// the two-dimensional array to restore my own magic square.
private int[][] myMagicSquare;
private int n;
public MagicSquare(){
}
/**
* Function: this constructor takes and positive, odd integer parameter to generate a new
* magic square.</br>
* @param n the length of magic square</br>
* @throws IllegalArgumentException for negative or even parameter.
* Preston Jul 5, 20151:15:40 AM</br>
*/
public MagicSquare(int n){
//throws runtime error.
if(!rangeCheck(n)){
throw new IllegalArgumentException("Illegal number");
}else{
// create my magic square array with length of given integer.
this.n = n;
myMagicSquare = new int[n][n];
// generate the magic square.
createMagicSquare();
}
}
/**
*
* Function: this constructor takes a 2D array as a parameter. If the 2D array can generate
* a magic square, then put the values into <i>my magic square</i></br>, if not then throws
* the exception.
* @param newMagicSquare the tested 2D array</br>
* @throws IllegalArgumentException
* Preston Jul 5, 20151:23:10 AM</br>
*/
public MagicSquare(int[][] newMagicSquare){
this.n = newMagicSquare.length;
// determine whether or not the 2D array can generate a magic square.
if(isMagic(newMagicSquare))
myMagicSquare = newMagicSquare;
else
throw new IllegalArgumentException("This is not a magic square");
}
/**
*
* Function:Range check for the input of magic square length</br>
* @param n the length of magic square
* @return true if the length is a positive, odd number</br>
* Preston Jul 5, 20152:53:29 PM</br>
*/
private static boolean rangeCheck(int n){
return !((n>0&&n%2==0)||n<=0);
}
/**
*
* Function: return the magic number of the magic square.</br>
* @return the value magic number.</br>
* Preston Jul 5, 20151:29:02 AM</br>
*/
private int getMagicNumber(){
return (n*(n*n+1))/2;
}
/**
*
* Function: For challenging level: check if all numbers for 1 to n*n only appeared once
* in the given 2D array.</br>
* @param temp the temporary 2D array as parameter.
* @return true if all numbers from 1 to n*n only appeared once</br>
* Preston Jul 5, 20151:30:03 AM</br>
*/
private static boolean noRepeatedNum(int[][] temp){
int n = temp.length;
// Set up the standard Set for comparison.
Set<Integer> standardSet = new HashSet<>();
for(int i=1;i<=n*n;i++){
standardSet.add(i);
}
// the Set made of all numbers from temp. All repeated numbers show only once in Set.
Set<Integer> arraySet = new HashSet<>();
for(int[] x : temp){
for(int a : x){
arraySet.add(a);
}
}
// return if two Sets are equal.
return arraySet.equals(standardSet);
}
/**
*
* Function: Check if the given 2D array can consist a magic square</br>
* @param temp a parameter 2D array.
* @return true if numbers in the parameter array could consist a magic square</br>
* Preston Jul 5, 20151:36:44 AM</br>
*/
private static boolean isMagic(int[][] temp){
//store the return value
boolean isMagic = true;
int tempN = temp.length;
int magicNumber = (tempN*(tempN*tempN+1))/2;
// accumulator for two diagonals
int diagonalOneSum = 0;
int diagonalTwoSum = 0;
// check rows and columns
for(int i=0; i<tempN;i++){
int rowSum = 0;
int columnSum = 0;
for(int j=0;j<tempN;j++){
// single-row sum
rowSum += temp[i][j];
// single-column sum
columnSum += temp[j][i];
}
if(rowSum!=magicNumber||columnSum!=magicNumber){
isMagic = false;
// return false immediately if there's inequality. Save calculations and performance.
return isMagic;
}
}
// counter for the second diagonal
int diagonalTwoCounter = tempN-1;
// sum of two diagonals
for(int i=0;i<temp.length;i++){
diagonalOneSum += temp[i][i];
diagonalTwoSum += temp[diagonalTwoCounter][diagonalTwoCounter];
diagonalTwoCounter--;
}
if(diagonalOneSum!=magicNumber||diagonalTwoSum!=magicNumber){
isMagic = false;
return isMagic;
}
// check if there are repeated numbers in the pretty magic square already.
return noRepeatedNum(temp);
}
/**
*
* Function: check if the position of the number in the magic square is at boundary</br>
* @param boundary the row OR column number of the position
* @return true if the value of<code>boundary</code> is zero</br>
* Preston Jul 5, 20151:53:24 PM</br>
*/
private boolean Boundary(int boundary){
return boundary==0;
}
/**
*
* Function: Put numbers from 1 to n*n into my own 2D array using Siamese Method.</br>
* Preston Jul 5, 20153:20:56 PM</br>
*/
private void createMagicSquare(){
// starting Row number -> middle
int startRow = this.n/2;
// starting Column number -> the first column
int startColumn = 0;
// start to put number from 2
int startNum = 2;
// put 1 in the starting position
myMagicSquare[startRow][startColumn] = 1;
while(startNum<=n*n){
// the positions on upper boundary
if(Boundary(startRow)&&!Boundary(startColumn)){
myMagicSquare[n-1][startColumn-1] = startNum;
startRow = n-1;
startColumn -= 1;
}
// the positions on left boundary
else if(Boundary(startColumn)&&!Boundary(startRow)){
myMagicSquare[startRow-1][n-1] = startNum;
startRow -= 1;
startColumn = n-1;
}
// upper left corner.
else if(Boundary(startRow)&&Boundary(startColumn)){
myMagicSquare[startRow][startColumn+1] = startNum;
startColumn += 1;
}
else{
// if the coming position is filled with number.
if(myMagicSquare[startRow-1][startColumn-1]!=0){
myMagicSquare[startRow][startColumn+1] = startNum;
startColumn += 1;
}
// general movement
else{
myMagicSquare[startRow-1][startColumn-1] = startNum;
startRow -= 1;
startColumn -= 1;
}
}
startNum++;
}
}
public String toString() {
// align my 2D array.
return toString(myMagicSquare);
}
/**
*
* Function:align the numbers in the parameter 2D array pretty</br>
* @param temp the parameter 2D array.
* @return the beautifully aligned String</br>
* Preston Jul 5, 20153:26:15 PM</br>
*/
public static String toString(int[][] temp){
int largestNum = 0;
// get the largest number in temp.
for(int[] x : temp){
for(int a : x){
if(a>=largestNum)
largestNum = a;
}
}
// how many digits does the biggest number have?
int longestDigit = String.valueOf(largestNum*largestNum).length();
// store the final String
StringBuilder printOut = new StringBuilder();
printOut.append('\n');
for(int[] x : temp){
for(int a : x){
// space between each number
printOut.append('\t');
// add spaces for alignment.
for(int i=0;i<longestDigit-String.valueOf(a).length();i++){
printOut.append(" ");
}
printOut.append(String.valueOf(a));
}
printOut.append('\n').append('\n');
}
// return the big String
return printOut.toString();
}
/**
*
* Function: the main function scans user input as the length of 2D array to make my
* own magic square. If the <code>userInput</code> is out of range, print out the error
* message and ask for the number again. Enter the code 0 to exit.</br>
* @param args</br>
* Preston Jul 5, 20153:28:57 PM</br>
*/
public static void main(String[] args) {
int userInput;
do{
// title
System.out.println("Enter a positive, odd number");
System.out.print("Exit code is 0, enter 0 to quit: ");
// user input
userInput = new Scanner(System.in).nextInt();
// if the userInput is out of range, show error message.
if(rangeCheck(userInput)){
MagicSquare m = new MagicSquare(userInput);
System.out.println(m.toString());
}else
if(userInput==0)
System.out.println("The magic square is not generated. QUIT");
else
System.err.println("Wrong number: Please enter a positive, odd number");
// restart
System.out.println("-------------------");
}while(userInput != 0); // enter 0 to exit.
}
}
最佳答案
出现上述问题的原因是eclipse 中处理stdout 和stderr 的错误。 Follow this link . (不确定这是否已修复。)
我也尝试重现这个问题，但它在某些情况下会发生，在某些情况下输出和错误输出显示在正确的位置。
只是为了检查:-
您可能会在第一次在 eclipse 上运行时遇到此问题，所以不要退出代码，使用错误的数字(即 2/4/6 ...)重试；您可能会看到错误并正确打印输出。
关于java - 从 Eclipse 和 cmd 运行的结果不同？ Java程序--魔方，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/31238374/