.. _hw11:

Homework 11 - No Tabs
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In a string, the tab character is '\\t' -- ASCI character 9.  The intent of
tabs is to line text up with consistent indenting.  Text editors often allow
the user to specify the number of space characters that a tab should fill.
Line printers often default to 8 characters for tabs, yet 4 characters per
indention level is more common for source code or other text files.  If tabs
are set to be every 4 characters, then the next character should be
displayed at the column that is an interger multiple of 4.  So if a line
consists of 13 characters, a tab and then more characters, then the second
set of characters should begin at column position 16, so in this case, the
tab should fill 2 character positions.

Write a C program to read a text file and replace any tab characters with
the appropriate number of spaces (ASCII character 32) to line up the text at
4 spaces per indention level.  The program may prompt the user to enter the
names of the input and output files.  Use the `fgetc()` function to read
the file and `fputc()` to write the data.