# inputif statement

The inputif statement captures input from the type-ahead buffer
 and assigns the input to a variable.

## Syntax

```
 inputif var {= expr} {,length-expr} {,fillchars} {_}
 {:} {from line-expr}
 then/else statement
 end
```

## Parameter(s)

| : | A colon suppresses the automatic line feed and carriage return when the value is input. |
| --- | --- |
| _ | An underscore specifies that a carriage return must be entered by the user, even if the input length equals length-expr. If the user tries to exceed the maximum length, a bell rings. |
| var = expr | Assigns input data to variable var. If expr is specified, var is initially set to the value of expr, and characters in the type-ahead buffer are appended to that value. |
| length-expr | An expression, up to 140 characters, to be interpreted as the maximum number of characters to assign to var. |
| fillchars | An expression evaluating to a string of one, two, or three characters. The first character is taken as a background mask for the input field, and the second is used as an overstrike filler for portions of the field left unwritten. The cursor returns to the end of the input data unless there is a third fill character. If there is a third fill character, the cursor remains at the end of the formatted field. |
| FROM line-expr | Take the input from the type-ahead of the attached line line-expr. If the line is not attached, a run-time error is printed and the BASIC Debugger is entered. |
| THEN statement | Executes a statement if the type-ahead buffer is not empty. |
| ELSE statement | Executes a statement if the type-ahead buffer is empty. |

## Description

The inputif statement checks the type-ahead buffer and, if it is
 non-null, initially assigns the variable *var* with the contents of
 the type-ahead buffer.

 After the contents are assigned, it executes the THEN part of the statement. If a
 maximum length (*length-expr*) has been specified with an
 underscore (_), pressing Enter is necessary. If there is no data in the type-ahead
 buffer, the variable is not assigned and the ELSE part of the statement is
 executed.

 If the type-ahead buffer is empty, the variable is not assigned and the user is not
 prompted. However, if the type-ahead buffer is not empty, but a carriage return is
 required to complete the input, the user is prompted with the type-ahead buffer
 input.

 The inputif statement includes many features reflecting those of
 the standard input statement. See [input statement](https://d3codex.com/pickbasic-flashbasic/input-statement/) for more information.

 The type-ahead feature can be controlled with the ta statement.
 The ta statement has options to turn on or off type-ahead and to
 clear the type-ahead buffer. Furthermore, the intrinsic function
 ta returns the number of characters in the type-ahead
 buffer.

## Example(s)

**Example 1**

 To assign the variable *TYPEA* with the current contents of the
 type-ahead buffer and print "TYPE AHEAD EMPTY" if no data is received, the code
 would read:

```

 INPUTIF TYPEA ELSE
 PRINT "TYPE AHEAD EMPTY"
 END
```

 **Example 2**

 In this example, a requested calculation might take several minutes to complete. The
 user is allowed to use the Esc key to exit from the program, and the
 inputif statement is repeated at every iteration to see if
 Escape was entered in the type-ahead buffer.

```

 PRINT "ENTER <ESC> TO EXIT."
 LOOP
 .
 .
 .
 LOOP
 INPUTIF STOPVAR,1 : THEN
 IF STOPVAR = CHAR(27) THEN
 GOSUB EXIT
 END
 TA.EMPTY = 0
 END ELSE
 TA.EMPTY = 1
 END
 UNTIL TA.EMPTY DO REPEAT
 .
 .
 .
 UNTIL ...DO REPEAT
```

## See also

- [input statement](https://d3codex.com/pickbasic-flashbasic/input-statement/)
- [statement blocks](https://d3codex.com/pickbasic-flashbasic/statement-blocks/)
- [Statements and functions](https://d3codex.com/pickbasic-flashbasic/statements-and-functions/)
- [ta statement](https://d3codex.com/pickbasic-flashbasic/ta-statement/)
- [then/else statement blocks](https://d3codex.com/pickbasic-flashbasic/then-else-statement-blocks/)

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