[GRASS-dev] correction to v.example

[Juan Diego Giraldo Osorio]

Hi everyone

I'm a beginner programmer in GRASS, but in the v.example code (main.c
file) I have found a little mistake in this line:

Vect_check_input_output_name ( new->answer, old->answer, GV_FATAL_EXIT );

The correct form (I think) is the next:

Vect_check_input_output_name ( old->answer, new->answer, GV_FATAL_EXIT );

Only shift "new" by "old", because the first function parameter is the
"input" file ("old") and the second funtion parameter is the "output"
file ("new").

Without this correction the error message was.

ERROR: Cannot find input map 'output_file'

I hope this message help to anothers beginners.