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CS558: Homework 1

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• Intro to Tcl Programming
  • This project will re-inforce what you learned about Tcl programming.

  • You don't need to be an expert in Tcl programming, but you need to know enough Tcl to use the language to construct a NS simulation program.

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• Preparation
  • In order to execute Tcl program, you need to have access to the ns2 command.

  • To gain access to the ns2 command, you need to add the path

    /home/cs558000/bin

    to your PATH environment variable. The best way to do this is to add this line in your start up file:

    PATH=$PATH:/home/cs558000/bin

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  • If you don't know what I am talking about (so don't know what to do), then run the following command:

    /home/cs558000/bin/add-kshrc

    After you run the command (and it ended successfully), logout, and log back it to make the changes take effect.

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• Project Assignment
  • Write a Tcl program named hw1.tcl that takes 2 arguments a and b and prints their greatest common divisor

  • The program must issue an error message when the number of arguments given is not equals to 2.

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• Example outputs
  • The following is a sample of outputs when the hw1.tcl program is executed:

    >> ns2 hw1.tcl Usage: ns2 hw1.tcl a b Program computes GCD of a abd b >> ns2 hw1.tcl 24 Usage: ns2 hw1.tcl a b Program computes GCD of a abd b >> ns2 hw1.tcl 24 36 GCD = 12

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• Turn in
  • You must turn in every assignment according to the instruction in the assignment page.

  • To turn in homework 1's file hw1.tcl, use this command to turn it in:

    /home/cs558000/turnin hw1.tcl hw1

    You will receive a message when the file is submitted successfully.