COMP2560- Lab 2 Solved

Notes:

 

•       You can only use system call open/close/read/write/lseek. No library I/O allowed.

•       You           may     be        given   different         text     files     for       lab       test.     Those  texts    may     include           line      feed,    tab,      space,  integer,           string  etc.     

 

 

Part     I.         

           

Write  a          C          program         called  writer.c.          It         uses    system            call      I/O      to         create a          file       called list1.txt           which  has      the      following        text-based      content:         

           

101    GM         Buick  2010  

102    Ford       Lincoln           2005  

           

There  are      three   blanks between         the      first     and      the      second            columns.         There  is         one      tab       between the      second            and      third,   and      between         the      third   and      fourth columns.        

           

You      can      only     call      function          write   once.   After   file       list1.txt           is         created,          type    the      following commands     to         check  the      content           of         the      file.      Make   sure    you      understand    how     characters      are internally       saved.

           

more   list1.txt                                   od        –c        list1.txt          

                                    od        –x        list1.txt          

           

           

Part     II.        

           

Write  a          C          program         called  change1.c.       Use      system            call      I/O      to         open   the      file       list1.txt,           and replace           the      string  101      with    integer 101.     After   executing       the      program,        type    the      following        commands to         check  the      content           of         the      file:     

           

                                                                                    more    list1.txt                       #          doesn’t            work   –          not      text-based!           

                                    od        –c        list1.txt          

                                    od        –x        list1.txt          

           

           

Part     III       

           

Consider         the      car       list       where the      first     and      second            columns          are      swapped,        with    a          tab between         them. 

           

GM    101   Buick         2010 

1          60-256 System Programming                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     Dr.       Chen   

Ford              102       Lincoln            2005  

           

Repeat Part     I           to         create this      text-based      list2.txt.           Use      lseek() to         write   a          program         called  change2.c. Similar            to         Part     II,         it          works on        list2.txt           to         replace           the      string  101      with    integer 101. Check  your    result.

 

 

 

             

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