System() call in nawk

[Quang Ngo]

I have a question about nawk.  Why does the command 'system' know id but
not f[i]?  It says

nawk: f[i]: No such file .....

However, if I change it to 

   if (system("grep id 1fl_87.txt") == 1)

then it works okay.

Thank you,

-Quang (quang at csufres.CSUFresno.EDU)

--------------------------
BEGIN {
	f[0] = "1fl_87.txt"
	f[1] = "2sp_88.txt"
	f[2] = "3fl_88.txt"
	f[3] = "4sp_89.txt"
	f[4] = "5fl_89.txt"
	f[5] = "6-SP90"
}

{
	id = substr($0,34,9)

	for (i=0; i<6; i++)
	if (system("grep id f[i]") == 1)    
		printf("%s %d\n",id,i)
}
--------------------------