在作为运行时输入输入后从锯齿状数组中检索元素

问题描述

我试图在运行时输入后打印锯齿状的数组元素。 但是在打印时，我无法这样做，因为它正在打印零。 有人可以帮我纠正这个吗？

import java.util.Scanner;
import static java.lang.System.out;
import static java.lang.System.in;

class JaggedArrayDemo2 
{
    public static void main(String[] args) 
    {   Scanner input = new Scanner(in);
        out.print("\nEnter the number of rows for the jagged array:\t");
        int row_length = input.nextInt();
        int column_length;
        int r, c;
        int[][] jar = new int[row_length][];

        out.println("\nEnter the number of columns for each row:");
        for (r=0; r<row_length ; r++)
        {   out.print("jar["+r+"]  =  ");
            column_length = input.nextInt();    
            jar[r] = new int[column_length];
        }

        out.println("\nEnter the individual elements:");
        for(r = 0; r<jar.length; r++)
        {   for(c = 0;  c < jar[r].length; c++)
            {   out.print("jar["+r+"]["+c+"]  =  ");
                input.nextInt();    }
        }

        out.println("\nThe resultant jagged array is:");
        for(r = 0; r<jar.length; r++)
        {   for(c = 0;  c < jar[r].length; c++)
            {out.print(jar[r][c]+"\t");}
            out.println("");
        }
    }
}

实际结果，存储在单个数组元素中的提示工作正常，但 for 循环读取没有任何更改，结果为 0。

D:\JavaEx\ARRAYS>java JaggedArrayDemo2

Enter the number of rows for the jagged array:  3

Enter the number of columns for each row:
jar[0]  =  4
jar[1]  =  2
jar[2]  =  3

Enter the individual elements:
jar[0][0]  =  1
jar[0][1]  =  2
jar[0][2]  =  3
jar[0][3]  =  4
jar[1][0]  =  5
jar[1][1]  =  6
jar[2][0]  =  7
jar[2][1]  =  8
jar[2][2]  =  9

The resultant jagged array is:
0       0       0       0
0       0
0       0       0

预期结果，仅用于打印：

The resultant jagged array is:
1       2       3       4
5       6
7       8       9

你有没有想过实际存储这些值？

    out.println("\nEnter the individual elements:");
    for(r = 0; r<jar.length; r++)
    {   for(c = 0;  c < jar[r].length; c++)
        {   out.print("jar["+r+"]["+c+"]  =  ");
            input.nextInt();    }
    }

...这段代码只要求用户输入，但它不会对输入做任何事情。 尝试使用以下代码将输入的数字存储在jar数组中：

    out.println("\nEnter the individual elements:");
    for(r = 0; r<jar.length; r++)
    {   for(c = 0;  c < jar[r].length; c++)
        {   out.print("jar["+r+"]["+c+"]  =  ");
            jar[r][c] = input.nextInt();    }
    }

以下将起作用。 在您的代码中，您没有将输入值存储在数组中。

替换input.nextInt()在第二for与循环jar[r][c] = input.nextInt()

package com.example;

import java.util.Scanner;

import static java.lang.System.in;
import static java.lang.System.out;

public class JaggedArrayDemo2 {

    public static void main(String[] args) {
        Scanner input = new Scanner(in);
        out.print("\nEnter the number of rows for the jagged array:\t");
        int row_length = input.nextInt();
        int column_length;
        int r, c;
        int[][] jar = new int[row_length][];

        out.println("\nEnter the number of columns for each row:");
        for (r = 0; r < row_length; r++) {
            out.print("jar[" + r + "]  =  ");
            column_length = input.nextInt();
            jar[r] = new int[column_length];
        }

        out.println("\nEnter the individual elements:");
        for (r = 0; r < jar.length; r++) {
            for (c = 0; c < jar[r].length; c++) {
                out.print("jar[" + r + "][" + c + "]  =  ");
                jar[r][c] = input.nextInt();
            }
        }

        out.println("\nThe resultant jagged array is:");
        for (r = 0; r < jar.length; r++) {
            for (c = 0; c < jar[r].length; c++) {
                out.print(jar[r][c] + "\t");
            }
            out.println("");
        }
    }
}

将输入存储在名为jar的二维数组中

改变

input.nextInt();

到

jar [r][c] = input.nextInt();

这是更新的代码片段

out.println("\nEnter the individual elements:");
    for (r = 0; r < jar.length; r++) {
        for (c = 0; c < jar[r].length; c++) {
            out.print("jar[" + r + "][" + c + "]  =  ");
            jar [r][c] = input.nextInt();
        }
    }

点击此处查看图片中

确切的解决方案：

package com.example;

import java.util.Scanner;

import static java.lang.System.in;
import static java.lang.System.out;

public class JaggedArrayDemo2 {

    public static void main(String[] args) {
        Scanner input = new Scanner(in);
        out.print("\nEnter the number of rows for the jagged array:\t");
        int row_length = input.nextInt();
        int column_length;
        int r, c;
        int[][] jar = new int[row_length][];

        out.println("\nEnter the number of columns for each row:");
        for (r = 0; r < row_length; r++) {
            out.print("jar[" + r + "]  =  ");
            column_length = input.nextInt();
            jar[r] = new int[column_length];
        }

        out.println("\nEnter the individual elements:");
        for (r = 0; r < jar.length; r++) {
            for (c = 0; c < jar[r].length; c++) {
                out.print("jar[" + r + "][" + c + "]  =  ");
                jar[r][c] = input.nextInt();
            }
        }

        out.println("\nThe resultant jagged array is:");
        for (r = 0; r < jar.length; r++) {
            for (c = 0; c < jar[r].length; c++) {
                out.print(jar[r][c] + "\t");
            }
            out.println("");
        }
    }
}