Initial Values (and the RESET Statement)

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# Initial Values (and the RESET Statement)

This document describes the default initial values of user-defined variables, explains how you can assign an initial value to a user-defined variable and how you can use the `RESET` statement to reset the field value to its default initial value or the initial value defined for that variable in the `DEFINE DATA` statement.

This document covers the following topics:

- Default Initial Value of a User-Defined Variable/Array

- Assigning an Initial Value to a User-Defined Variable/Array

- Resetting a User-Defined Variable to its Initial Value

Note
For example definitions of assigning initial values to arrays, see Example 2 - DEFINE DATA (Array Definition/Initialization) in the Statements documentation.

## Default Initial Value of a User-Defined Variable/Array

If you specify no initial value for a field, the field will be initialized with a default initial value depending on its format:

Format | Default Initial Value
--- | ---
B, F, I, N, P | `0`
A, U | blank
L | `F(ALSE)`
D | `D' '`
T | `T'00:00:00'`
C | (`AD=D`)
GUI Handle | `NULL-HANDLE`
Object Handle | `NULL-HANDLE`

## Assigning an Initial Value to a User-Defined Variable/Array

In the `DEFINE DATA` statement, you can assign an initial value to a user-defined variable. If the initial value is alphanumeric, it must be enclosed in apostrophes.

- Assigning a Modifiable Initial Value

- Assigning a Constant Initial Value

- Assigning a Natural System Variable as Initial Value

- Assigning Characters as Initial Value for Alphanumeric/Unicode Variables

### Assigning a Modifiable Initial Value

If the variable/array is to be assigned a modifiable initial value, you specify the initial value in angle brackets with the keyword `INIT` after the variable definition in the `DEFINE DATA` statement. The value(s) assigned will be used each time the variable/array is referenced. The value(s) assigned can be modified during program execution.

Example:

    DEFINE DATA LOCAL
    1 #FIELDA (N3) INIT <100>
    1 #FIELDB (A20) INIT <'ABC'>
    END-DEFINE
    ...

### Assigning a Constant Initial Value

If the variable/array is to be treated as a named constant, you specify the initial value in angle brackets with the keyword `CONSTANT` after the variable definition in the `DEFINE DATA` statement. The constant value(s) assigned will be used each time the variable/array is referenced. The value(s) assigned cannot be modified during program execution.

Example:

    DEFINE DATA LOCAL
    1 #FIELDA (N3) CONST <100>
    1 #FIELDB (A20) CONST <'ABC'>
    END-DEFINE
    ...

### Assigning a Natural System Variable as Initial Value

The initial value for a field may also be the value of a Natural system variable.

Example:

In this example, the system variable `*DATX` is used to provide the initial value.

    DEFINE DATA LOCAL
    1 #MYDATE (D) INIT <*DATX>
    END-DEFINE
    ...

### Assigning Characters as Initial Value for Alphanumeric/Unicode Variables

As initial value, a variable can also be filled, entirely or partially, with a specific character string (only possible for variables of the Natural data format A or U).

- Filling an entire field:
  With the option `FULL LENGTH <character-string>`, the entire field is filled with the specified characters.

  In this example, the entire field will be filled with asterisks.

      DEFINE DATA LOCAL
      1 #FIELD (A25) INIT FULL LENGTH <'*'>
      END-DEFINE
      ...

- Filling the first n positions of a field:
  With the option `LENGTH n <character-string>`, the first `n` positions of the field are filled with the specified characters.

  In this example, the first 4 positions of the field will be filled with exclamation marks.

      DEFINE DATA LOCAL
      1 #FIELD (A25) INIT LENGTH 4 <'!'>
      END-DEFINE
      ...

## Resetting a User-Defined Variable to its Initial Value

The `RESET` statement is used to reset the value of a field. Two options are available:

- Reset to Default Initial Value

- Reset to Initial Value Defined in DEFINE DATA

Notes:

1. A field declared with a `CONSTANT` clause in the `DEFINE DATA` statement may not be referenced in a `RESET` statement, since its content cannot be changed.
2. In reporting mode, the `RESET` statement may also be used to define a variable, provided that the program contains no `DEFINE DATA LOCAL` statement.

### Reset to Default Initial Value

`RESET` (without `INITIAL`) sets the content of each specified field to its default initial value depending on its format.

Example:

    DEFINE DATA LOCAL
    1 #FIELDA (N3)  INIT <100>
    1 #FIELDB (A20) INIT <'ABC'>
    1 #FIELDC (I4)  INIT <5>
    END-DEFINE
    ...
    ...
    RESET #FIELDA                    /* resets field value to default initial value
    ...

### Reset to Initial Value Defined in DEFINE DATA

`RESET INITIAL` sets each specified field to the initial value as defined for the field in the `DEFINE DATA` statement.

For a field declared without `INIT` clause in the `DEFINE DATA` statement, `RESET INITIAL` has the same effect as `RESET` (without `INITIAL`).

Example:

    DEFINE DATA LOCAL
    1 #FIELDA (N3)  INIT <100>
    1 #FIELDB (A20) INIT <'ABC'>
    1 #FIELDC (I4)  INIT <5>
    END-DEFINE
    ...
    RESET INITIAL #FIELDA #FIELDB #FIELDC /* resets field values to initial values as defined in DEFINE DATA
    ...

### On this page

- Default Initial Value of a User-Defined Variable/Array
- Assigning an Initial Value to a User-Defined Variable/Array
- Resetting a User-Defined Variable to its Initial Value