Question

我正在尝试编写一个程序，它将提示用户输入1到9之间的数字，并将创建一个矩阵x x，其中x是给定的数字。它应该产生从1到x ^ 2的随机数来填充矩阵。我找到了它，如果我输入'5'我得到一行5个随机数字然后四行只有一个数字。我错过了什么？

import java.util.Scanner;
import java.util.Random;
public class MatrixFiller
{
  public static void main(String[] args)
  {
    //Getting input from the user
    Scanner input = new Scanner(System.in);
    System.out.print("Size of Matrix(a number between 1 and 9): ");
    int matrixn = input.nextInt();
    input.close();
    //max is the largest possible number that can be calculated
    //with the given number squared.
    int max = (matrixn * matrixn);
    //Counters for building the matrix
    int i = 0;
    int j = 0;
    //Will create a line with x numbers on it but then produces
    //x lines with only one number. If given 5 it produces a
    //line with 5 numbers then four more lines with one number
    //each.
        do {
          do {
            Random rand = new Random();
            int mout = rand.nextInt(max - 0);
            System.out.print(mout + " ");
            i++;
          }
          while (i < matrixn);
          System.out.println();
          j++;
        }
        while (j < matrixn);

  }
}

Answer 1

您需要在循环开始时重置i，否则它仍然是前一行的matrixn。

do {
    i = 0;  // It won't work without this
    do {
        Random rand = new Random();
        int mout = rand.nextInt(max - 0);
        System.out.print(mout + " ");
        i++;
    } while (i < matrixn);
    System.out.println();
    j++;
} while (j < matrixn);

虽然这有效，但使用for循环会更好。

Answer 2

关键是在第一个i循环的顶部将do的值重置为零。

或者您可以使用for循环，因为它似乎更清洁：

Random rand = new Random();
for (i=0; i<matrixn; i++) {
    for (j=0; j<matrixn; j++) {
        int mout = rand.nextInt(max);
        System.out.print(mout + " ");
    }
    System.out.println();
}

Answer 3

你的内循环只执行一次，我必须从每次请求开始。

  do{
     i = 0 ;
     do {
        Random rand = new Random();
        int mout = rand.nextInt(max – 0);
        System.out.print(mout +  “ “);
        i ++;
     } while(i<matrixn);
     system.our.println();
     j++;
  } while(j < matrixn);

在Java中创建数字矩阵

3 个答案: