使用二维整数数组

Question

Basically, I need to prompt the user for the rows and columns of an array without asking how many rows and columns there are. How do I improve the following code to do that?

    System.out.println("Please input the first set of integers separated by spaces" );
    String givenSet1 = console.readLine();

    set1 = givenSet1.split(" ");
    set1Values = new int[set1.length];

    for(int i = 0; i < set1.length; i++)
    {
        set1Values[i] = Integer.parseInt(set1[i]);
    }

    while(counter <= set1Values.length)
    {
        numbers = new int[set1Values.length][];
        numbers[counter] = set1Values[counter];
    }

    for(int a = 0; a < set1Values.length; a++)
    {
        System.out.println("Please input the set of integers that are to be associated with    element " + a + ", separated by spaces" );
        String givenSet2 = console.readLine();

        set2 = givenSet2.split(" ");
        set2Values = new int[set2.length];

        numbers[a] = new int[set2Values.length];
        System.out.println(numbers[a]);

        for(int b = 0; b < set2Values.length; b++)
        {

        }
    }

Answer 1

您可以使用Array.length()函数返回数组中的元素数。

Answer 2

Your question is unclear and it is difficult to understand what you are trying to do from your code but I took a shot in the dark...

It seems as if you want to create a two dimensional array based on the user's input. The total amount of numbers inputted by the user would define the amount of columns in the array, with the user providing a set integers to store as associated numbers for each of those columns. The result would be a two dimensional array as long as the user always entered the same amount of numbers to associate with each column, but just incase I coded it to create a jagged array.

Code:

import java.util.Scanner;  

public class Create2DArray {

    public static void main(String[] args)
    {

        int[][] jaggedArray; //declare 2D array
        String[] userInput;  //declare array for user input
        String[] userInput2; //declare array for ints to associate with first input

        Scanner input = new Scanner(System.in); //scanner to read 

        System.out.println("Please input the first set of integers separated by spaces: " );      
        userInput = input.nextLine().split(" "); //parsing first set of string input

        jaggedArray = new int[userInput.length][];  //create 2D array based on no. of columns defined in first set of user input       

        // array elements will be referenced by x and y, like coordinates.
        for (int x = 0; x < jaggedArray.length; x++) //cycle through first set of numbers to prompt for associate numbers
        {
            System.out.println("Please input the set of integers that are" +
                               "to be associated with element " + userInput[x] + ", separated by spaces: " );
            userInput2 = input.nextLine().split(" "); //parse and store the set to be associated with userInput[x] 

            jaggedArray[x] = new int[userInput2.length + 1]; //create a new int array in column x of jagged array, +1 to hold userInput[x] then associated values

            for (int y = 0; y < jaggedArray[x].length; y++) // cycle through the new array @ column x
            {
                if (y == 0)
                    jaggedArray[x][y] = Integer.parseInt(userInput[x]); //if y = 0 then copy the "column header" first
                else
                    jaggedArray[x][y] = Integer.parseInt(userInput2[y-1]); // else copy the new elements at position y-1 due to jagged array being +1 more than userInput2 array
            }       
        }      


        System.out.println();

        for (int x = 0; x < jaggedArray.length; x++) //cycling through the array to print it all
        {
            System.out.print("For integer: " + jaggedArray[x][0] + 
                             " the following integers are associated with it. ");

            for (int y = 1; y < jaggedArray[x].length; y++)
            {
                System.out.print(jaggedArray[x][y] + " ");                
            }     

            System.out.println();                   
        }      
    }
}

Next time please try to provide more information about your desired end results as well as more complete example code. It would be slightly easier to understand your code and requirements if we knew certain things such as what type of objects some of the variables in your example were. The more information the better.

Hopefully this won't be too hard to follow, and it's what you actually wanted.