The [[ASC (statement)|ASC]] statement allows a '''QB64''' program to change a character at any position of a [[STRING]] variable.


{{PageSyntax}} 
: [[ASC (statement)|ASC]]({{Parameter|stringExpression$}}[, {{Parameter|position%}}]) = {{Parameter|code%}}


{{PageDescription}}
* The {{Parameter|stringExpression$}} variable's value must have been previously defined and cannot be an empty string ("").
* {{Parameter|position%}} is optional. If no position is used, the leftmost character at position 1 is assumed.
* {{Parameter|position%}} cannot be zero or greater than the string's [[LEN|length]] or an [[ERROR Codes|Illegal function error]] will occur.
* The [[ASCII]] replacement {{Parameter|code%}} value can be any [[INTEGER]] value from 0 to 255.
* Some [[ASCII]] control characters will not [[PRINT]] a character or may format the [[SCREEN]]. [[_PRINTSTRING]] can print them graphically.


{{PageExamples}}
''Example:'' Demonstrates how to change existing text characters one letter at a time.
{{CodeStart}}
 a$ = "YZC"
 {{Cl|ASC (statement)|ASC}}(a$) = 65                 ' CHR$(65) = "A"
 {{Cl|ASC (statement)|ASC}}(a$, 2) = 66              ' CHR$(66) = "B"
 {{Cl|PRINT}} a$ 'ABC

 {{Cl|ASC (statement)|ASC}}(a$, 2) = 0               ' CHR$(0) = " " 
 {{Cl|PRINT}} a$

 {{Cl|ASC (statement)|ASC}}(a$, 2) = {{Cl|ASC}}("S")        ' get code value from ASC function
 {{Cl|PRINT}} a$
{{CodeEnd}}

{{OutputStart}}
 ABC
 A C
 ASC
{{OutputEnd}}


{{PageSeeAlso}}
* [[ASC]] {{text|(function)}}
* [[MID$ (statement)]]
* [[_PRINTSTRING]]
* [[INKEY$]], [[ASCII]]


{{PageNavigation}}