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DECLARE

Declares a procedure and directs QBasic to perform type checking for each parameter.

Syntax

DECLARE {FUNCTION SUB} procedure_name[( [ argument_list ] )]

Notes

DECLARE directs QBasic to ensure that the types of parameters passed to a procedure match the types that the procedure expects.

DECLARE is needed only when you don’t use the CALL keyword.

The keyword FUNCTION indicates that the procedure is a function; likewise, SUB indicates a subprogram.

procedure_name is the name of the function or subprogram.

argument_list is an optional list of parameters separated by commas. For compiler type checking, specify arguments as follows: variable_name[ AS type]

Valid types include INTEGER, LONG, SINGLE, DOUBLE, STRING, ANY, or a user-defined type. ANY allows any type for that parameter.

Example

DECLARE SUB SwapVal (a, b)

a = 1
b = 2
CALL SwapVal(a, b)
PRINT a; b
END

SUB SwapVal(x, y)
  temp = x
  x = y
  y = temp
END SUB

Running this program produces the following:

2  1

See Also