如何用用戶輸入的值填充二維數組？

Question

我目前正在用 java 編寫一個程序，用用戶輸入的值填充二維數組。 當行和列都指定為相同的值（方陣）時，該程序可以完美運行。 但是，當值不同時，它不會打印並拋出索引越界異常，我似乎無法弄清楚原因。 我在下面附上了我的代碼。

public static void main(String[] args) {
    Scanner console = new Scanner(System.in);
    int x; //columns
    int y; //rows

    System.out.println("Enter the number of rows of the matrix:");
    y = console.nextInt();
    System.out.println("Enter the number of columns of the matrix:");
    x = console.nextInt();

    int[][] matrix = new int[y][x];
    fillMatrix(y, x, matrix);
}

public static void fillMatrix(int row, int col, int[][] matrix) {
    Scanner console = new Scanner(System.in);
    int quantity = (row * col); //number of numbers in matrix
    System.out.println("Please enter " + quantity +
            " integers separated by spaces:");
    for (int cinput = 0; cinput < row; cinput++) { //column
        for (int rinput = 0; rinput < col; rinput++) { //row
            //Read the line of integers to fill positions in the array.
            matrix[cinput][rinput] = console.nextInt();
        }
    }
    System.out.println();
    for (int i = 0; i < col; i++) {
        for (int j = 0; j < row; j++) {
            //Outputs the array in a xy grid.
            System.out.print(matrix[i][j] + " ");
        }
        System.out.println();
    }
}

Answer 1

我要做的是復制您需要放入矩陣的所有數字。 持有一個計數器，該計數器僅在您將一個值放入矩陣時才會增加。 繼續增加計數器，直到沒有更多值可以放置。 完成后，只需退出循環即可。

像這樣的東西

Scanner myScanner = new Scanner (System.in);
int x; //columns
int y; //rows 
System.out.println("Enter the number of rows of the matrix:");
y = myScanner.nextInt();
System.out.println("Enter the number of columns of the matrix:");
x = myScanner.nextInt();

int [][] matrix = new int [x][y]; 


myScanner.nextLine();
System.out.println("Enter the numbers seperated by space:");
String input = myScanner.nextLine();

String tmp            [] = input.split(" "); //holds the numbers that are inputted (String)
int    numbers        [] = new int[tmp.length];//array that holds the parsed numbers

for(int i = 0 ; i <numbers.length; i++)
  numbers[i] = (int)(tmp[i].charAt(0) - '0');  //parsing the numbers

// Logic that matters
int counter = 0; 

for(int k = 0; k < matrix.length && counter < numbers.length; k++)
{
 for(int j = 0 ; counter < numbers.length &&  j < matrix[k].length; j++)
 {
     matrix[k][j] = numbers[counter];
     System.out.print(matrix[k][j]+" ");
     counter = counter + 1; 
 }
 System.out.println("");
}

輸入-

Enter the number of rows of the matrix:
3
Enter the number of columns of the matrix:
1
Enter the numbers seperated by space:
1 2 3

輸出 -

1 2 3

Answer 2

在您的輸出代碼中，更改i和j的順序。

所以改變：

matrix[i][j]

到：

matrix[j][i]

您可能也應該交換 for 循環的順序，這樣行在外面，列在里面。

放在一起，看起來像：

System.out.println();
for(int j = 0; j < row; j++)
{
    for(int i = 0; i < col; i++)
    {
        System.out.print(matrix[j][i] + " ");
    }
    System.out.println();
}