Exercise 1-10 | Together C & C++ | Page 1

junior holly Aug 31, 2023, 4:31 AM

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Write a program to copy its input to its output, replacing each tab by \t, each
backspace by \b, and each backslash by \. This makes tabs and backspaces visible in an unambiguous way.

I am not getting how do I test for backspace and I am not sure if I am doing it correctly, please review and give me some feedbacks.

#include <stdio.h>

main() {
  int c;

  while ((c = getchar()) != EOF) {
    if (c == '\t') {
      putchar(92);
      putchar(116);
    } else if (c == '\b') {
      putchar(92);
      putchar(98);
    } else if (c == '\\') {
      putchar(92);
      putchar(92);
    } else {
      putchar(c);
    }

  };
}

final basin Aug 31, 2023, 4:38 AM

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The backspace character is '\b' as clearly written there, you just compare normally.

junior holly Aug 31, 2023, 4:44 AM

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yes that part I am clear about it but how do I test while running this application?
if I hit backspace button will it generate \b?

iron moth Aug 31, 2023, 4:47 AM

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oh I think I get it
your terminal is line-buffered, so the backspaces aren't actually making it to stdin
is that right?

junior holly Aug 31, 2023, 4:48 AM

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yes

iron moth Aug 31, 2023, 4:48 AM

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bingo

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which os are you on?

junior holly Aug 31, 2023, 4:48 AM

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what can I do?

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arch

iron moth Aug 31, 2023, 4:48 AM

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nice

junior holly Aug 31, 2023, 4:48 AM

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using kitty

iron moth Aug 31, 2023, 4:48 AM

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gimme 2 seconds

junior holly Aug 31, 2023, 4:48 AM

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whats nice about it hehe?

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okay

final basin Aug 31, 2023, 4:50 AM

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junior holly yes that part I am clear about it but how do I test while running this applicati...

You can use a file.

junior holly Aug 31, 2023, 4:52 AM

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I am only at the first chapter and not sure which library or function to do I use to read the file.

final basin Aug 31, 2023, 4:52 AM

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You can pipe the file on the command-line.

iron moth Aug 31, 2023, 4:54 AM

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how on god's green earth do you write a backspace to a file

junior holly Aug 31, 2023, 4:54 AM

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will that work as reading the character from stdin?

final basin Aug 31, 2023, 4:54 AM

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Yes.

junior holly Aug 31, 2023, 4:54 AM

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iron moth how on god's green earth do you write a backspace to a file

yes my second question

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hehe

final basin Aug 31, 2023, 4:54 AM

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The file then is the stdin.

final basin Aug 31, 2023, 4:55 AM

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iron moth how on god's green earth do you write a backspace to a file

In vim I can press ^V^H to insert a backspace character.

iron moth Aug 31, 2023, 4:55 AM

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good to know

junior holly Aug 31, 2023, 4:55 AM

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whats that

final basin Aug 31, 2023, 4:56 AM

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What specifically?

iron moth Aug 31, 2023, 4:56 AM

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I swear there's a way to turn off line buffering in the terminal tho
using bash set or something
or was it ansi escapes?

junior holly Aug 31, 2023, 4:56 AM

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so you use control+V V right?

final basin Aug 31, 2023, 4:57 AM

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Ctrl+V then Ctrl+H.

junior holly Aug 31, 2023, 4:58 AM

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ok will try it thanks

iron moth Aug 31, 2023, 4:59 AM

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oh printf does work (go figure)

printf '\b' | ./your-program

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(run in your terminal)

junior holly Aug 31, 2023, 4:59 AM

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nice

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so okay so thats workings thanks guys and what about the logic is putchar(92); putting asci only the way to do this?

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is there any better way to do this?

final basin Aug 31, 2023, 5:03 AM

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'\\'.

iron moth Aug 31, 2023, 5:10 AM

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characters are just integers:

characters in C (char) are an integral type (it's better to think of them as "bytes" than "characters")
character constants in C are integers, confusingly (yes, I mean int, not char)

#Exercise 1-10