# Determine the Upper Bound of a Two Dimensional Array in Java

• Last Updated : 26 Oct, 2020

Multidimensional arrays in Java are common and can be termed as an array of arrays. Data in a two-dimensional array in Java is stored in 2D tabular form. A two-dimensional array is the simplest form of a multidimensional array. A two-dimensional array can be seen as an array of the one-dimensional array for easier understanding. A two-dimensional array is declared with two dimensions that are also referred to as their bounds.

Syntax of an Array of Arrays:

```data_type[][] array_name = new data_type[x][y];
```

For example: int[][] arr = new int;    // 20 X 30 array of arrays

Direct Declaration of an Array of Arrays:

```data_type[][] array_name = {
{valueR1C1, valueR1C2, ....},
{valueR2C1, valueR2C2, ....}
};
```

For example: int[][] arr = {{1, 2}, {3, 4}};

Allocation of values in an Array of Arrays

## Java

 `// Allocation of values in an Array of Arrays ` `class` `GFG { ` `    ``public` `static` `void` `main(String[] args) ` `    ``{ ` ` `  `        ``int``[][] arr = ``new` `int``[``20``][``30``]; ` `        ``arr[``0``][``0``] = ``100``; ` ` `  `        ``System.out.println(``"arr = "` `+ arr[``0``][``0``]); ` `    ``} ` `}`

Output

`arr = 100`

Printing complete Array of Arrays

## Java

 `// Printing complete Array of Arrays ` `class` `GFG { ` `    ``public` `static` `void` `main(String[] args) ` `    ``{ ` ` `  `        ``int``[][] arr = { { ``1``, ``2` `}, { ``3``, ``4` `} }; ` ` `  `        ``for` `(``int` `i = ``0``; i < ``2``; i++) ` `            ``for` `(``int` `j = ``0``; j < ``2``; j++) ` `                ``System.out.println(``"arr["` `+ i + ``"]["` `+ j ` `                                   ``+ ``"] = "` `+ arr[i][j]); ` `    ``} ` `}`

Output

```arr = 1
arr = 2
arr = 3
arr = 4```

An array of Arrays in java is actually an array of a one-dimensional array. Each row of a two-dimensional array has a length field that holds the number of columns. However, we can get both the row upper bound and the column dimensions using:

```int row_bound = array_name.length;
int column_bound = array_name.length;
```

Determine the Dimension of an Array of Arrays

## Java

 `// Determine the Dimension of an Array of Arrays ` `class` `GFG { ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `        ``int``[][] arr = ``new` `int``[``10``][``20``]; ` `        ``int` `row_bound = arr.length; ` `        ``int` `column_bound = arr[``0``].length; ` `        ``System.out.println(``"Dimension 1: "` `+ row_bound); ` `        ``System.out.println(``"Dimension 2: "` `+ column_bound); ` `    ``} ` `}`

Output

```Dimension 1: 10
Dimension 2: 20```

Note: It is important to understand that Java doesn’t really have two-dimensional arrays. Java arrays are inherently jagged. It has arrays of arrays. So there is no one upper bound/length of the column level.

Example:

## Java

 `// row bound and column bounds ` `class` `GFG { ` `    ``public` `static` `void` `main(String args[]) ` `    ``{ ` `        ``int``[][] arr = { { ``1``, ``2` `}, ` `                        ``{ ``3` `}, ` `                        ``{ ``4` `}, ` `                        ``{ ``5``, ``6``, ``7``, ``8` `}, ` `                        ``{ ``9``, ``10``, ``11``, ``12``, ``13``, ``14``, ``15` `} }; ` `        ``int` `row_bound = arr.length; ` `        ``int` `column_bound1 = arr[``0``].length; ` `        ``int` `column_bound2 = arr[``1``].length; ` `        ``int` `column_bound5 = arr[``4``].length; ` `        ``System.out.println(``"Dimension 1: "` `+ row_bound); ` `        ``System.out.println(``"Dimension 2: "` `+ column_bound1); ` `        ``System.out.println(``"Dimension 3: "` `+ column_bound2); ` `        ``System.out.println(``"Dimension 4: "` `+ column_bound5); ` `    ``} ` `}`

Output

```Dimension 1: 5
Dimension 2: 2
Dimension 3: 1
Dimension 4: 7```

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