---
title: Java
shortTitle: 
category:
  - Java
tag:
  - &
description: JavaJavaJava
head:
  - - meta
    - name: keywords
      content: Java,Java SE,Java,Java,Java,Java,Java,,java,
---

# 4.2 





### 01

34

```java
array = [
  [a, b, c, d],
  [e, f, g, h],
  [i, j, k, l]
]
```

444 array[1][2] 23 g



### 02

 Java 



```txt
data_type[][] array_name;
```



```java
int[][] oddNumbers = { {1, 3, 5, 7}, {9, 11, 13, 15} };
```


###  03







```java
int[][] oddNumbers = { {1, 3, 5, 7}, {9, 11, 13, 15} };

System.out.println(oddNumbers[0][0]);
// 1
```

`oddNumbers` `{1, 3, 5, 7}`  `{9, 11, 13, 15}`

`{1, 3, 5, 7}` 0 

`{9, 11, 13, 15}` 1 

 0 1 2

 0  0`oddNumbers[0][0]`



`oddNumbers[?][?]`



`oddNumbers[1][?]`

`{9, 11, 13, 15}`

 `13``oddNumbers[1][2]`



```java
int[][] oddNumbers = { {1, 3, 5, 7}, {9, 11, 13, 15}, {17, 19, 21, 23} };
```

 21`oddNumbers[?][?]`



 0 => `{1, 3, 5, 7}`

 1 => `{9, 11, 13, 15}`

 2 => `{17, 19, 21, 23}`

`oddNumbers[2][?]`



17 =>  0

19 =>  1

21 =>  2

23 =>  3

21  2`oddNumbers[2][2]` 21



```java
int[][] oddNumbers = { {1, 3, 5, 7}, {9, 11, 13, 15}, {17, 19, 21, 23} };

System.out.println(oddNumbers[2][2]);
// 21
```



```java
int[][] oddNumbers = { {1, 3, 5, 7}, {9, 11, 13, 15}, {17, 19, 21, 23} };

for(int i = 0; i < oddNumbers.length; i++){
    for(int j = 0; j < oddNumbers[i].length; j++){
        System.out.println(oddNumbers[i][j]);
    }   
}

// 1
// 3
// 5
// 7
// 9
// 11
// 13
// 15
// 17
// 19
// 21
// 23
```

 `oddNumbers` 

### 04





```java
import java.util.Scanner;

public class YangHuiTriangle {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("");
        int n = input.nextInt();
        printYangHuiTriangle(n);
    }

    public static void printYangHuiTriangle(int n) {
        int[][] triangle = new int[n][n];

        for (int i = 0; i < n; i++) {
            // 1
            triangle[i][0] = 1;
            triangle[i][i] = 1;

            for (int j = 1; j < i; j++) {
                // 
                triangle[i][j] = triangle[i - 1][j - 1] + triangle[i - 1][j];
            }
        }

        // 
        for (int i = 0; i < n; i++) {
            for (int j = 0; j