# dimension statement

The dimension statement establishes
a specific number of storage locations for a matrix of variables.

**Synonyms:** dim

## Syntax

```
 dimension array.var({rows{,cols}})
```

## Parameter(s)

| array.var | Can be of one or two dimensions only. Individual elements within an array are accessed by appending the element number, enclosed in parentheses, to the array variable. |
| --- | --- |
| rows | Number of rows in the array. Can be any valid numeric expression. |
| cols | Number of columns in the array. Can be any valid numeric expression. |

## Description

A dimension statement without the number of elements specified (such as in the
case dim a()) can only be used in a subroutine.
FlashBASIC or BASIC run time determines the number of elements after
a matread.

An array must be dimensioned prior to being referenced within a program. After an array has been
 dimensioned, it can be re-dimensioned later within a program. When the dimensioning parameters
 are changed, the new array:

- Retains those elements with the same indexes that were in the old array.

- Initializes any new elements to an unassigned state.

- Loses any un-referenced elements (those elements in the old array with indexes not present in the new array).

If an array is passed to a subroutine in an argument list, it cannot be re-dimensioned within the
 subroutine. A passed array can only be dimensioned once within a subroutine. Local arrays can be
 re-dimensioned as necessary. When arrays are dimensioned both in a subroutine and within the
 calling program, the dimensions specified in the calling program supersede those specified
 within the subroutine if the subroutine’s array was dimensioned as an empty dimension. The
 number of dimensions must be the same in both the calling program and called subroutine.

## Example(s)

**Example 1**

- rec is a single dimensional array (vector) with 20 sub-scripted variables.

- table is a two-dimensional array (matrix) with 9 subscripted variables.

```

 dim rec(20),table(3,3)
```

 **Example 2**

The dim statement can be handled by FlashBASIC or BASIC runtime.

```

 x = 20
 dim a(x)
 input y
 dim b(y)
 dim c(x,y)
```

 **Example 3**

This example illustrates a dim statement
without arguments. It resolves the size of the array after the matread.

```

 subroutine process.receipt(work.list)
 dim work.list()
 ...
 matread work.list...
```

## See also

- [mat statement](https://d3codex.com/pickbasic-flashbasic/mat-statement/)
- [matbuild statement](https://d3codex.com/pickbasic-flashbasic/matbuild-statement/)
- [matparse statement](https://d3codex.com/pickbasic-flashbasic/matparse-statement/)
- [matread statement](https://d3codex.com/pickbasic-flashbasic/matread-statement/)
- [matreadu statement](https://d3codex.com/pickbasic-flashbasic/matreadu-statement/)
- [matwrite statement](https://d3codex.com/pickbasic-flashbasic/matwrite-statement/)
- [matwriteu statement](https://d3codex.com/pickbasic-flashbasic/matwriteu-statement/)

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Source: https://d3codex.com/pickbasic-flashbasic/dimension-statement/ - part of the D3Codex reference.