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//----------------------------------------------------------------------------//

// Program: Permutations of string -> number of permutations = factorial len( string )
// Date:    08/02/2010
// Autor:   Cristobal Navarro
//----------------------------------------------------------------------------//

#include "fivewin.ch"

Static cString
Static aString
Static aTmpString

Function Main()

    local x
    aString      := {}
    aTmpString   := {}
    cString      := "ABC"
    SetArray()
    Permutations( 1, Len( cString ) )
    ? Len( aString )
    //AEVal( aString, { | a | a := Val( a ) } )
    XBrowse( aString )          //Add 23/05/2016
Return nil

//----------------------------------------------------------------------------//

Function Permutations( nIni, nLen )

   local x
   if nIni <> nLen
      For x = nIni to nLen
         SwapArray( nIni, x )
         Permutations( nIni + 1, nLen )
         SwapArray( nIni, x )          
      Next x
   else
      AAdd( aString, SetString() )
   endif

Return nil

//----------------------------------------------------------------------------//

Function SwapArray( nIni, nAct )

    local cTemp
    cTemp  := aTmpString[ nIni ]
    aTmpString[ nIni ] := aTmpString[ nAct ]
    aTmpString[ nAct ] := cTemp

Return nil

//----------------------------------------------------------------------------//

Function SetArray()

   local x
   For x = 1 to Len( cString )
       AAdd( aTmpString, Substr( cString, x, 1 ) )
   Next x

Return nil

//----------------------------------------------------------------------------//

Function SetString()

   local x
   local cCad   := ""
   For x = 1 to Len( aTmpString )
      cCad += aTmpString[ x ]
   Next x

Return cCad

//----------------------------------------------------------------------------//