Random number in AutoIt is not working -

the intention of string generate random number in format: l = letter n = num,

llnnn 

instead, gives me this:

nn 

or sometimes:

n 

code

local $destination = "c:\users\ryan\pictures\aurora.jpg"  if random() < 1     $lettera = chr(random(asc("a"), asc("z"))) endif if random() < 1     $letterb = chr(random(asc("a"), asc("z"))) endif if random() < 1     $numbera = chr(random(48, 57, 1)) endif if random() < 1     $numberb = chr(random(48, 57, 1)) endif if random() < 1     $numberc = chr(random(48, 57, 1)) endif  splashimageon("splash", $destination, 312, 146, 450, 300, 1) sleep(9000) splashoff() if msgbox(1, "code generator", "create new key?") = 1     msgbox(0, "code generator", "your registry is:" + $lettera + $letterb + $numbera + $numberb + $numberc) endif 

you assign string value , append @ end.

local $destination = "c:\users\ryan\pictures\aurora.jpg"  if random() < 1     $lettera = chr(random(asc("a"), asc("z"))) endif if random() < 1     $letterb = chr(random(asc("a"), asc("z"))) endif if random() < 1     $numbera = chr(random("48", "57", "1")) endif if random() < 1     $numberb = chr(random("48", "57", "1")) endif if random() < 1     $numberc = chr(random("48", "57", "1")) endif  splashimageon("splash", $destination, 312, 146, 450, 300, 1) sleep(9000) splashoff() if msgbox(1, "code generator", "create new key?") = 1     msgbox(0, "code generator", "your registry is:" & $lettera & $letterb & $numbera & $numberb & $numberc) endif