Text and Binary File Processing

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Chapter 12

• Text and Binary File Processing
• (Hanly)

2
Objectives

• We will explore the use of standard input,
  standard output, and program-controlled text
  files.
• We will introduce binary files.
• We will compare the advantages and disadvantages
  of text and binary files.

3
Input/Output Files Review and Further Study

• Text file a named collection of characters saved
  in secondary storage (e.g. on a disk).
• To mark the end of a text file a special
  end-of-file character. lteofgt
• Pressing the ltreturngt or ltentergt key causes the
  newline character to be placed in the file.
  (\n).
• This is a text file!ltnewlinegt
• It has two lines.ltnewlinegtlteofgt
• This is a text file!ltnewlinegtIt has two
  lines.ltnewlinegtlteofgt

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The Keyboard Screen as Text Streams

• Input (output) steam continuous stream of
  character codes representing textual input (or
  output) data.
• stdin system file pointer for keyboards input
  stream.
• stdout, stderr system file pointers for
  screens output system.
• All these streams can be treated like text files
  because their individual components are
  characters.

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Escape Sequences

• \n new line
• \t tab
• \f form feed (new page) ??
• \r return (go back to column 1 of current
  output line)
• \b backspace
• Demo

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Formatting Output with printf
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File Pointer Variables

• Chap 2
• FILE infilep
• FILE outfilep
• infile fopen(data.txt,r)
• outfile fopen(results.txt,w)
• Unsuccessful due to the nonexistence of a file.
• if (infilep NULL)
• printf(Cannot open data.txt for input)
• Closing a File fclose(infilep)

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I/O with Standard Files and with User-Defined
File Pointer
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Demo Program to Make a Backup Copy of a Text
File(demo)
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Input and Output Streams for File Backup Program
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Binary Files

• Files containing binary numbers that are the
  computers internal representation of each file
  component.
• Creating a Binary File of Integers

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• binaryp fopen(nums.bin,wb)
• wb write binary
• rb read binary
• fwrite(i, sizeof(int), 1, binaryp)
• i the address of the first memory cell whose
  contents are copied to the file.
• sizeof(int) the number of bytes to copy to the
  file for one component. sizeof can be applied to
  both bulit-in and user-defined types.
• 1 the number of values to write to the binary
  file.

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Advantages of Binary files

• Assume that two bytes are used store an int
  value.
• 244 (1286432164)
• 11110100
• In text files,
• Write 11110100 ? 2 4 4 and blank
• Read 244 ? 11110100
• It takes more time.
• It takes more space. (Four bytes versus two)
• Precision

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A Negative Side of Binary files

• A binary file created on one computer is rarely
  readable on another type of computers.
• A binary file can not be created or modified in a
  word processor.
• fread ?? fwrite
• fscanf ?? fprintf