Replace 3th letter in a string

BioDuo
13th December 2005 09:07 UTC

Replace 3th letter in a string
How do I replace the third letter in a string

Example

$0 ReadRegStr HKCU "Software\BioDuo" "BioDuo"

Now, $0 contains 123456 but should be replace with 123556
123456 is a user entered number so it can be different on each computer so I can't use the Replace function.

How can I do this?

-BioDuo

Afrow UK
13th December 2005 15:53 UTC

Function Replace3rdLetter
Exch $R0
Exch
Exch $R1
Exch
Exch 2
Exch $R2
Exch 2
Push $R3
StrCpy $R3 $R0 $R2
IntOp $R2 $R2 + 1
StrCpy $R0 $R0 "" $R2
StrCpy $R0 $R3$R1$R0
Pop $R3
Pop $R2
Pop $R1
Exch $R0
FunctionEnd
!macro Replace3rdLetter RetVar ReplaceInStr ReplaceWithChar ReplaceAtIndex
 Push "${ReplaceAtIndex}"
 Push "${ReplaceWithChar}"
 Push "${ReplaceInStr}"
  Call Replace3rdLetter
 Pop "${RetVar}"
!macroend
!define Replace3rdLetter '!insertmacro Replace3rdLetter'

Usage:
${Replace3rdLetter} $R0 "123456" "5" "4"
$R0 = 123556

Made this in college without a compiler so it is untested.
Also, you said you want the 3th (3rd) character replaced, but your example of 123456 > 123556 replaces the 4th character. The last parameter of ${Replace3rdLetter} specifies the index to replace; replacing it with the value of the 3rd parameter.

-Stu