blog/pb071/bonuses/08.md

---
id: seminar-08
title: 8th seminar
description: |
  Manipulating with files only char-by-char and a magic tree.
---

# 8th seminar bonus assignment

[Source](pathname:///files/pb071/bonuses/08/)

## Introduction

In this bonus you can implement two tasks, one of them has a bonus part with generic
solution.

One is focused on counting ananas or in case of generic version any substring in
the file, but with a restriction on the function you use.

Other one has a more algorithmic spirit.

For this bonus you can get at maximum 2.5 K₡.

## Warning

**DO NOT COMMIT test data** to your own git repository, since the tests include
files that exceed 10MB by themselves. Even if they are on separate branch, they
take up the space.

## Testing

For testing you are provided with python script (requires `click` to be installed:
`pip3 install --user click`) and `Makefile` that provides following targets:

- `check-counting` - runs the `counting` tests
- `check-counting-bonus` - runs the `counting` tests with bonus implemented
- `check` - runs both `counting` and `counting-bonus` tests
- `clean` - removes output files from the test runs

## Task no. 1: Counting (0.75 K₡)

Your first task is to make smallish program that counts occurences of specific
(or given) word from file and writes the number to other file.

Usage of the program is:

```
Usage: ./counting <input-file> <output-file> [string-to-be-counted]
```

Arguments that are passed to the program represent:

- `<input-file>` - path to the file where we count the words
- `<output-file>` - path to the file where we output the count
- (optional argument) `[string-to-be-counted]` - in case you implement bonus,
  otherwise we default to word `ananas` ;)

In skeleton you are given 3 empty, but documented, functions to implement.

1. `count_anything` - function accepts input file and substring to be counted in
   the file, returns the count.
2. `count_ananas` - same as `count_anything`, but specialized for ananases, the
   default implementation from the skeleton expects you to implement `count_anything`
   and therefore it just calls the other function.
3. `write_number` - function that writes the number to the file, why would you
   need the function is explained later :)

### Requirements

For manipulation with the files you are only allowed to use `fopen`, `fclose`,
`fgetc` and `fputc`. Functions like `fprintf` (except for `stderr` or logging) and
`fscanf` are **forbidden**.

In case you struggle and want to use one of those functions, the solution will be
penalized by 50% of points.

### Bonus part (0.75 K₡)

Bonus part of this assignment is to implement `count_anything` rather than `count_ananas`.

> Smaller hint: This task does not need dynamic allocation :) You just need one
> good helper function and the right idea ;)

## Task no. 2: Weird trees (1 K₡)

In this task we are crossing our paths with _algorithms and data structures_.
Your task is to write a program that constructs tree from the file that is given
as an argument and pretty-prints it.

Input file consists of lines, that include `key` and `rank` in form `key;rank`
or `nil`. Why would we have `nil` in a file? The file represents pre-order iteration
through the tree. Leaves never have rank different than 0, so you can safely assume
2 non-existing `nil`s in the input after you read such node ;)

<table><tr>
<td>
Example input file

```
8;4
5;3
3;2
2;1
1;0
nil
4;0
7;1
6;0
nil
11;2
10;1
9;0
nil
12;0
```

</td>
<td>
Tree it represents

![tree](/files/pb071/bonuses/08/tree.png)

</td>
</tr></table>

In this task you are only provided with different trees in the `test-trees` directory.
Implementation and format of the pretty-print is totally up to you. :)

Example of mine for the tree above:

```
8 (rank = 4)
+-- 5 (rank = 3)
|   +-- 3 (rank = 2)
|   |   +-- 2 (rank = 1)
|   |   |   +-- 1 (rank = 0)
|   |   +-- 4 (rank = 0)
|   +-- 7 (rank = 1)
|       +-- 6 (rank = 0)
+-- 11 (rank = 2)
    +-- 10 (rank = 1)
    |   +-- 9 (rank = 0)
    +-- 12 (rank = 0)
```

> Can you find out what are those trees? :)

## Submitting

In case you have any questions, feel free to reach out to me.

---

Ideally submit the assignment through the merge request. Step-by-step tutorial is
present [here](../mr). For setting assignee my xlogin is `xfocko`.

In case you do not want to experiment on GitLab, send me the source code via email,
but please prefix subject with: `[PB071/14][seminar-08]`

Deadline for the submission of the bonus is **May 4th 24:00**.