IO statement

  $\blacktriangleright$ PRINT

 
The   statement displays the value of it single argument.

  $\blacktriangleright$ SYSTEM

 
The   statement executes the UNIX command given by its single argument.

$\vartriangleright$ Example 14:Run the 'make' command in a X terminal

 

   SYSTEM("xterm -e make")

  $\blacktriangleright$ OPEN

 
The      function opens a file. Its first argument is the file name. The second argument is a string that describe the opening mode:

• "r" = open for reading
• "w" = truncate to zero length or create for writing
• "a" = append; open for writing at end of file, or create for writing

The obsolete predefined constants RD="r", WR="w" and AP="a" are available. The OPEN function returns the file descriptor used by CLOSE and WRITE.

  $\blacktriangleright$ CLOSE

 
The   function closes the file specified by its single argument.

  $\blacktriangleright$ WRITE

 
The   function writes the value of its second argument in the file specified by its first argument.

$\vartriangleright$ Example 15:

     

   fid := OPEN("myfile.txt") 
   year := 1998 
   WRITE(fid,"IRISA ")  
   WRITE(fid,year)  
   CLOSE(fid)