>And why i need to doubts in VFP when I write:
>

STR(15,9)

>i know the result. And what happen when the result is
>

'     15  '
> 123456789

>and I don't know this.

CLEAR
_screen.resettodefault("FontName")
? "|"+STR(15,9)+"|"
? "|"+"123456789"+"|"
_screen.FontName = "Courier New"

? "|"+STR(15,9)+"|"
? "|"+"123456789"+"|"

when the alignment checks him it always needs to keep in mind the font.