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Lab 1 Solution

1. Write two small c programs.




1). The first program "pre.c" should read in a list of U.S. states and their populations. You can google to find the information. To be simple, you can use the abbreviation for each state. We assume there are at most 10 states in the list. Enter the input through the keyboard and display the output on the screen. The input ends when an EOF is encountered. The output of the program should display the states whose population is above 10 million.




 

For example, the following are the inputs to "pre.c". The unit is million.







TX 26

NC 9

MD 5

NY 19

CA 38

Ctrl-D (to terminate the input.)

 

then "pre.c" produces the output:

TX

NY

CA




Note: an EOF is usually 'sent' to a process by hitting a CTRL_D.

If you type stty -an on your unix command line, you can get info that

tells you which keyboard keys mean what. FYI, in c, to put values to

standard_out use printf(). To get values from standard_in use scanf()

or getchar().




2). The second program "sort.c" reads in a list of state abbreviations from stdin and

display them in alphabetical order on the screen. Assume there are no more than 10 states and the

sequence is read until an EOF is encountered.




If the inputs are:




TX

NY

CA




The outputs should be:




CA

NY

TX

 




2. Write a c program to set up a child-TO-parent pipe; the child

should 'exec' to perform a "pre" process and its output should be

connected to the pipe connected to the parent, which should 'exec' to

perform a "sort" process.




3. Write a program to take a UNIX command from the command line

and fork() a child to execute it. The command can be a simple

command like: $ls or $ps, Or it can be a command with options such as

$ls -t -l. Use argc and argv[] in the main function to pass parameters.

When the child process is executing the command, the parent process

simply waits for the termination of the child process. The process

id of the parent and the child should be printed out using getpid() and

getppid() functions.




 

Submission:




In order not to lose any files, you'd better zip all your files into a .zip file.




Submit your project to TRACS. You should write a readme textfile telling the grader how to run your programs. Without this file, it is very likely that your project will not be run properly.







 

 

 

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