ch1/10.c

   1 /*
   2  * Example 1-10:
   3  * Write a program to copy its input to its output, replacing each tab by \t, each backspace by \b,
   4  * and each backslash by \\.  This makes tabs and backspaces visible in an unambiguous way.
   5  */
   6
   7 // NOTE: On most modern systems, backspaces will not show up, because of buffered output.
   8
   9 #include <stdlib.h>
  10 #include <stdio.h>
  11
  12 /*
  13  * Print this when we need to show a special character.
  14  * It itself is escaped, because a backslash is also a special character!
  15  */
  16 #define ESC_CHAR '\\'
  17
  18 int
  19 main(void)
  20 {
  21         // Read all input until EOF.
  22         int c;
  23         while ((c = getchar()) != EOF)
  24                 // Show special characters by printing ESC_CHAR and then a letter.
  25                 switch (c) {
  26                         case '\t':
  27                                 putchar(ESC_CHAR);
  28                                 putchar('t');
  29                                 break;
  30                         case '\b':
  31                                 putchar(ESC_CHAR);
  32                                 putchar('b');
  33                                 break;
  34                         case ESC_CHAR:
  35                                 putchar(ESC_CHAR);
  36                                 putchar(ESC_CHAR);
  37                                 break;
  38                         default:
  39                                 putchar(c);
  40                 }
  41
  42         return EXIT_SUCCESS;
  43 }