text: /*copy input to output replacing tab by \t, each backspace by \b and backslash by // */
  #include <stdio.h>
  main()
  {
      int c;
  
      while ((c = getchar()) != EOF)
          if(c == '\t')
              printf("\\t");
          else if (c == '\b')
              printf("\\b");
          else if (c == '\\')
              printf("\\\\");
          else
              putchar(c);
  }
  
  