Java 2D Array学习

Question

我有这个练习Java代码,我正在努力完成.显而易见的问题是,当我尝试打印时array[1][2],它返回null,所以我认为数组可能是空的.如何将用户输入放入数组中？

import java.util.Scanner;
public class Studyone {


    public static void main(String[] args) 
    {
        Scanner input = new Scanner(System.in);
        int row = 13;
        int col = 25;
        String sentence;
        String sentence2;
        String [][] map = new String[row][col];
        for (int i = 0; i < map.length; i++) 
        {
            for (int j = 0;i < map.length; i++) 
            {
                System.out.println("Enter the element");
                sentence2 = input.nextLine();
                map[i][j]=sentence2;
                if (row>col)
                {
                    break;
                }
            }
        }
        System.out.println(map[1][2]);
    }
}

Answer 1

更改

for (int j = 0;i < map.length; i++) 

至

for (int j = 0;j < map[0].length; j++) 

例如,假设x = new int[3][4],x[0],x[1],和x[2]是一维数组,并且每个包含四个元件,如该图所示x.length是3,和 x[0].length,x[1].length和x[2].length是4