Diff Tool Task

Write a program that compares (at least) two text files.

• The files to compare shall be specified on the command line.
• The output should be per different line, on stdout.
• You are encouraged to make changes to the provided skeleton.
• You are expected to write additional tests to cover larger files and potential edge-cases.

Skeleton Contents

• main.c with an example main() function;
• include/ with some headers suggesting modules that you may want to implement in src/;
• tests/ with sample input files & expected output, divided into solution stages;
• run_tests.py so you don't spend more time in the terminal than in your editor.
• Makefile to build the project.

Building & Testing

Linux:

• cd bld && make; cd .. (or enter the commands separately)
• ./run_tests.py 0 (where 0 is the stage you're testing)
  • If your build is broken: make clean from bld/

Windows:

• cd bld; mingw32-make.exe; cd ..
• python.exe run_tests.py 0 (where 0 is the stage you're testing)
  • If your build is broken: mingw32-make.exe clean from bld\

You may want to add extra compiler options in CFLAGS or specify extra source and include directories in the makefile.

---

Solution Stages

Not all diffs are created equal.

You are strongly encouraged to implement the program in increasing levels of functionality and sophistication.

The skeleton suggests the following stages:

Stage-0

Check files for strict equality. Meaning any difference is considered a negative, and no difference - a positive.

Suggested output:

"Files are identical." or "Files are different."

Stage-1

Count the number of non-identical lines. For each line, compare only its counterpart (so don't take added or deleted lines into account).

Suggested output:

"Files are identical.", "1 line differs.", or "15 lines differ."

Stage-2

Print the lines of each file that differ. If one file is longer than the other, also show the extra lines.

Suggested output:

Left 3: hello
Right 3: hi
Right 4: there

Stage-3

Your own design and tests. This is what will be evaluated.