N*N矩阵的Java实现
这是我写的:
import javax.swing.JOptionPane;
public class JavaTest{
public static void main(String[] args){
String numberString = JOptionPane.showInputDialog(null, "Enter number here: ",
null, JOptionPane.INFORMATION_MESSAGE);
int number = Integer.parseInt(numberString);
printMatrix(number);
}
public static void printMatrix(int n){
int[][] myList = new int[n][n];
String output = "";
for (int row = 1; row <= n; row++){
for (int col = 1; col <= n; col++){
myList[row][col] = (int) (Math.random() * 2);
}
}
for (int row = 1; row <= n; row++){
for (int col = 1; col <= n; col++){
if (col == n){
output += "\n" + myList[row][col];
}
else{
output += myList[row][col] + " ";
}
}
}
if (n < 0){
JOptionPane.showMessageDialog(null,
"Invalid input!");
}
else{
JOptionPane.showMessageDialog(null,
output);
}
}
}
我运行它并在对话框中输入3,EclipseIDE显示
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 3
at JavaTest.printMatrix(JavaTest.java:17)
at JavaTest.main(JavaTest.java:8)
我猜第17行和第8行的程序出错了,但我不知道如何改进它。 如何改进代码?谢谢
# 1 楼答案
您正在从1循环到n:
索引从0开始,而不是从1开始。循环应在0到n-1之间:
(除了抛出异常的第一行之外,此错误可能还存在于其他位置。)