Question

我正在尝试创建一个填充了1-99随机数的方阵。我已经设置了这个，但是超过7个维度的任何东西都会返回错误，我不确定原因。

每次我开始超过最大尺寸时，它会突破不同。

package matrix;
import java.util.Arrays;
import java.util.Scanner;
import  java.util.Random;

public class Matrix {

static int dim;

public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);
    String repeat="yes";
    do
        {if (dim<=25)
            {//prompt user for dimensions, only need one number
                System.out.println("Please enter the dimensions of the matrices. Enter       one number that is greater or equal to 25.");
                dim=sc.nextInt();
             //all rows and columns are equal
         matrices m1 = new matrices(dim);
         m1.randomFill();
         m1.printMatrix();

             System.out.print("\n Would you like to repeat the program? (yes/no)");
                repeat=sc.next();
            }
        else 
            {System.out.print("Invalid dimensions, pleasse enter a number greater or equal to 25.");
            dim=sc.nextInt();
            }
        }
    while (repeat.trim().equalsIgnoreCase("yes"));

    }

 }

public class pool {

//instance variables
private int size;
static int [] poolArray;
private Random ridx;

//constructors
public pool (int sz)
{size = sz;
poolArray = new int [sz];
ridx = new Random ();
}

//instance methods
public void fillPool ()
{for(int n=0; n<size; n++)
    {poolArray [n]=n+1;
    }
}

public int randomValue ()
    {int idx = ridx.nextInt(size);
    int rval = poolArray [idx];
    size--;
    poolArray [idx] = poolArray [size];
    return (rval);
    }    

 public static void main(String[] args) {
 pool p1 = new pool (99);
 {p1.fillPool ();}

 System.out.println(poolArray[0]+", "+poolArray[25]+", "+poolArray[98]);
 System.out.println(p1.randomValue());
}      
}
public class matrices {
static int [][] m;
static int size;
static pool p1 = new pool (99);
 {p1.fillPool ();}
static pool p2 = new pool (99);
 {p1.fillPool ();}

 matrices (int dimension)
 {m=new int [dimension][dimension];
 size=dimension;}

static void randomFill ()
 {int i, j; // loop counters
for (i=0;i<size;i++)
      { for(j=0;j<size;j++)
        m[i][j]=p1.randomValue();
          }
 }

   static void printMatrix()
{   int i, j;   // loop counters
for (i=0;i<size;i++)
      { for(j=0;j<size;j++)   
    System.out.print(m[i][j] + "  ");
    System.out.println("");    
  }
    System.out.println(""); 
}

}

这是出现的错误：

   Exception in thread "main" java.lang.IllegalArgumentException: n must be positive 
   at java.util.Random.nextInt(Random.java:300) at matrix.pool.randomValue(pool.java:34)        
   at matrix.matrices.randomFill(matrices.java:28) at matrix.Matrix.main(Matrix.java:30) Java     
   Result: 1

Answer 1

请格式化您的代码！

但如果rids.nextInt(size) size < 0，则integer overflow会抛出错误如果你有一个> Integer.MAX_VALUE，那么你就可以尝试存储一个整数{{1}}，可能，由于溢出而产生负值。此行为因整数而异。

NxN矩阵填充随机数1-99

1 个答案: