我创建了一个对象和客户端类，它按照距离原点的距离顺序打印坐标。客户端类询问用户他们希望数组有多少维度（x，y或x，y，z）他们想要生成多少个点，以及每个坐标将从哪个维度运行的范围（例如-x到x） ，-y到y等）。当我运行程序时，它打印出正确数量的点，但是数组中总有一个额外的元素（等等当用户输入数组的维度为'4'时，它总是打印出一个额外的元素 - ＆gt; [4 ，5,9,6,1]）。为什么会这样？
客户等级
import java.io.*;
public class MA {
public MA() { }
public static void main(String args[]) throws IOException {
String myString = "arrayNumPoints.txt";
int numpoints = 0;
int dimension = 0;
double lengthscale = 0;
double [][] points = new double[numpoints][dimension + 1];
BufferedReader myInput = new BufferedReader(new InputStreamReader(System.in));
MB pointsB = new MB();
System.out.println("Enter number of points:");
String numpointsA = myInput.readLine();
numpoints = Integer.parseInt(numpointsA);
pointsB.setnumpoints(numpoints);
System.out.println("Enter the dimension:");
String dimensionA = myInput.readLine();
dimension = Integer.parseInt(dimensionA);
pointsB.setdim(dimension);
System.out.println("Enter length(range):");
String lengthscaleA = myInput.readLine();
lengthscale = Double.parseDouble(lengthscaleA);
pointsB.setlengthscale(lengthscale);
pointsB = new MB(numpoints, lengthscale, dimension, points);
pointsB.fillarray(pointsB.getarray(), pointsB.getlengthscale(), pointsB.getdim(), pointsB.getnumpoints());
pointsB.caldistance(pointsB.getarray(), pointsB.getnumpoints(), pointsB.getdim());
pointsB.sort(pointsB.getarray(), 0, pointsB.getnumpoints()-1, pointsB.getdim());
pointsB.writefile(pointsB.getarray(), pointsB.getnumpoints(), myString);
pointsB.readfile(myString);
}
}
对象类
import java.io.*;
import java.util.Arrays;
public class MB {
//variables and arrays are declared
private double lengthscale;
private int numpoints;
private int dimension;
private double [][] points;
//constructor
public MB() { }
//constructor
public MB(double [][] points) {
numpoints = 0;
lengthscale = 0;
dimension = 0;
points = new double[numpoints][dimension + 1];
}
//constructor
public MB(int mynumpoints, double mylengthscale, int mydimension, double [][] mypoints) {
numpoints = mynumpoints;
lengthscale = mylengthscale;
dimension = mydimension;
points = new double[numpoints][dimension + 1];
}
//numpoints getter
public int getnumpoints()
{
return numpoints;
}
//numpoints setter
public void setnumpoints(int mynumpoints) {
numpoints = mynumpoints;
}
//lengthscale getter
public double getlengthscale() {
return lengthscale;
}
//lengthscale setter
public void setlengthscale(double mylengthscale) {
lengthscale = mylengthscale;
}
//dimension getter
public int getdim() {
return dimension;
}
//dimension setter
public void setdim(int mydimension) {
dimension = mydimension;
}
//array getter
public double[][] getarray() {
return points;
}
//array setter
public void setarray(double [][]mypoints, int numpoints, int dimension) {
points[numpoints][dimension] = mypoints[numpoints][dimension];
}
//fill array method
public void fillarray(double [][]mypoints, double mylengthscale, int mydimension, int mynumpoints) throws IOException {
for(int x = 0; x < mynumpoints; x++)
{
for(int y = 0; y < mydimension; y++) {
//fills array with random points within the specified range
mypoints[x][y] = (dimension * Math.random() - 1) * mylengthscale;
}//end for
}//end for
}
//writefile method
public void writefile(double [][]mypoints, int mynumpoints, String myString) throws IOException {
//writes to myString
PrintWriter fileOut = new PrintWriter(new FileWriter(myString));
//for loop runs for length of mylengthscale
for(int m = 0; m < mynumpoints; m++) {
//prints points to file
fileOut.println(Arrays.toString(mypoints[m]));
}
//close file
fileOut.close();
//end for
}
//readfile metod
public void readfile(String myString) throws IOException
{
String filePath = myString;
//reads data from mString
BufferedReader in = new BufferedReader(new FileReader(new File(myString)));
String line = null;
while(( (line = in.readLine()) != null))
System.out.println(line);
in.close();
}
//caldistance method
public void caldistance(double [][]mypoints, int mynumpoints, int mydimension) {
//for loop; calculates distance for specified number of points
for(int i = 0; i < mynumpoints; i++) {
for(int k = 0; k < mydimension; k++) {
mypoints[i][mydimension] = mypoints[i][k] * mypoints[i][k];
}//end for loop
mypoints[i][mydimension] = Math.sqrt(mypoints[i][mydimension]);
}//end for loop
}
//sort method
public double[][] sort(double[][] mynewpoints, int down, int top, int mydimension) {
System.arraycopy(mynewpoints, 0, mynewpoints, 0, mynewpoints.length);
//variables are declared
int d = down;
int u = top;
//determines pivot point
double [] pivot = mynewpoints[(down + top)/2];
//sorts the values of the array, comparing it to the pivot
do {
while (mynewpoints[d][mydimension] < pivot[mydimension]) {
d++;
}
while (mynewpoints[u][mydimension] > pivot[mydimension]) {
u--;
}
if (d <= u) {
double[] temporary = new double[mynewpoints[d].length];
//compres values in array and switches them
for (int y = 0; y < mynewpoints[d].length; y++) {
temporary[y] = mynewpoints[d][y];
mynewpoints[d][y] = mynewpoints[u][y];
mynewpoints[u][y] = temporary[y];
}
d++;
u--;
}
} while (d <= u);
if (down < u) {
mynewpoints = sort(mynewpoints, mydimension, down, u);
}
if (d < top) {
mynewpoints = sort(mynewpoints, mydimension, d, top);
}
return mynewpoints;
}
}
答案 0 :(得分：0)
您应该更具体（向我们展示您使用的代码片段以及出错的代码片段。）
但是你意识到，在你的MB构造函数中：
//constructor
public MB(double [][] points) {
numpoints = 0;
lengthscale = 0;
dimension = 0;
points = new double[numpoints][dimension + 1];
}
最后一行没有做任何事情？你必须这样写：
this.points = new double[numpoints][dimension + 1];
因为你有两个变量points，一个是类变量，第二个是作为参数传递的。如果发生这种情况，则不使用this选择非类变量。
答案 1 :(得分：0)
可能是因为您要将1添加到用户提供的维度中：
points = new double[numpoints][dimension + 1];
这导致数组的列数多于dimension的值。