# Reports:Tasks not implemented in ALGOL 68

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**ALGOL 68**is a language you like, or are interested in, please inform your fellow members of the ALGOL 68 community; this page can't be emptied without your and their participation.

## Contents

## Not implemented[edit]

These are currently not implemented in ALGOL 68. Please implement some if you can. If any tasks are not possible or too complex in ALGOL 68, they should not be on this list. To mark a task as such, add **{{omit from|ALGOL 68}}**, preserving the capitalization of the language, to that task. It will appear below under the "Not Considered" section.

### A

- AVL tree
- Active Directory/Connect
- Active Directory/Search for a user
- Active object
- Aliquot sequence classifications
- Animate a pendulum
- Animation
- Append a record to the end of a text file
- Archimedean spiral
- Arena storage pool
- Arithmetic-geometric mean/Calculate Pi
- Atomic updates
- Average loop length
- Averages/Mean time of day
- Averages/Mode

### B

- Barnsley fern
- Benford's law
- Bernoulli numbers
- Best shuffle
- Bitcoin/address validation
- Bitcoin/public point to address
- Bitmap/Bézier curves/Quadratic
- Bitmap/Flood fill
- Bitmap/Histogram
- Bitmap/PPM conversion through a pipe
- Bitmap/Read a PPM file
- Bitmap/Read an image through a pipe
- Bitmap/Write a PPM file
- Brace expansion
- Break OO privacy
- Brownian tree
- Bulls and cows/Player

### C

- Call a function in a shared library
- Call an object method
- Canny edge detector
- Casting out nines
- Catmull–Clark subdivision surface
- Chaos game
- Chat server
- Check Machin-like formulas
- Checkpoint synchronization
- Chinese remainder theorem
- Chinese zodiac
- Closest-pair problem
- Color of a screen pixel
- Color quantization
- Colour bars/Display
- Colour pinstripe/Display
- Colour pinstripe/Printer
- Combinations with repetitions
- Compare sorting algorithms' performance
- Compile-time calculation
- Compiler/lexical analyzer
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Conjugate transpose
- Continued fraction/Arithmetic/Construct from rational number
- Convert decimal number to rational
- Create a file on magnetic tape
- Create an object at a given address
- Cut a rectangle

### D

- DNS query
- Date manipulation
- Deal cards for FreeCell
- Death Star
- Deconvolution/1D
- Deconvolution/2D+
- Deepcopy
- Determine if only one instance is running
- Dining philosophers
- Discordian date
- Distributed programming
- Documentation
- Draw a clock
- Draw a cuboid
- Draw a rotating cube
- Draw a sphere
- Dutch national flag problem

### E

### F

- FASTA format
- FTP
- Farey sequence
- Fibonacci word/fractal
- Find largest left truncatable prime in a given base
- Find palindromic numbers in both binary and ternary bases
- Find the last Sunday of each month
- Find the missing permutation
- First class environments
- Flipping bits game
- Floyd-Warshall algorithm
- Formal power series
- Four bit adder
- Fractal tree
- Function frequency

### G

- GUI/Maximum window dimensions
- GUI component interaction
- GUI enabling/disabling of controls
- Galton box animation
- General FizzBuzz
- Generate Chess960 starting position
- Get system command output
- Globally replace text in several files
- Go Fish
- Grayscale image
- Greyscale bars/Display
- Guess the number/With feedback (player)

### H

### K

### L

### M

- MAC Vendor Lookup
- MD4
- MD5/Implementation
- Machine code
- Magic squares of doubly even order
- Magic squares of singly even order
- Main step of GOST 28147-89
- Make directory path
- Matrix arithmetic
- Maze generation
- Maze solving
- Median filter
- Metronome
- Minesweeper game
- Morse code
- Mouse position
- Multiple regression
- Munching squares

### N

### P

- Paraffins
- Parallel Brute Force
- Parallel calculations
- Parametric polymorphism
- Parametrized SQL statement
- Parse an IP Address
- Parsing/Shunting-yard algorithm
- Password generator
- Pathological floating point problems
- Pattern matching
- Penney's game
- Pentagram
- Percentage difference between images
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Percolation/Mean run density
- Percolation/Site percolation
- Permutation test
- Permutations/Derangements
- Permutations/Rank of a permutation
- Permutations by swapping
- Pig the dice game
- Pig the dice game/Player
- Pinstripe/Display
- Pinstripe/Printer
- Plasma effect
- Play recorded sounds
- Polynomial long division
- Polyspiral
- Primes - allocate descendants to their ancestors
- Primorial numbers
- Priority queue
- Problem of Apollonius
- Pythagoras tree
- Pythagorean triples

### R

- RCRPG
- RIPEMD-160
- Random number generator (device)
- Ranking methods
- Rate counter
- Ray-casting algorithm
- Read a configuration file
- Record sound
- Reflection/Get source
- Reflection/List methods
- Reflection/List properties
- Rendezvous
- Resistor mesh
- Respond to an unknown method call
- Rosetta Code/Count examples
- Rosetta Code/Find bare lang tags
- Rosetta Code/Find unimplemented tasks
- Rosetta Code/Fix code tags

### S

- SHA-1
- SHA-256
- SOAP
- SQL-based authentication
- Safe addition
- Sailors, coconuts and a monkey problem
- Same Fringe
- Secure temporary file
- Self-referential sequence
- Send an unknown method call
- Send email
- Set
- Set consolidation
- Set of real numbers
- Set puzzle
- Show the epoch
- Sierpinski pentagon
- Sierpinski triangle/Graphical
- Simple database
- Simple windowed application
- Simulate input/Keyboard
- Simulate input/Mouse
- Singleton
- Sockets
- Sokoban
- Solve a Hidato puzzle
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Solve the no connection puzzle
- Sort a list of object identifiers
- Sort disjoint sublist
- Sort stability
- Sort using a custom comparator
- Sorting algorithms/Bead sort
- Sorting algorithms/Comb sort
- Sorting algorithms/Permutation sort
- Sorting algorithms/Sleep sort
- Sorting algorithms/Strand sort
- Sparkline in unicode
- Speech synthesis
- Stable marriage problem
- Stack traces
- Start from a main routine
- State name puzzle
- Statistics/Basic
- Statistics/Normal distribution
- Stem-and-leaf plot
- Stern-Brocot sequence
- Strip block comments
- Subtractive generator
- Sum and Product Puzzle
- Superellipse
- Sutherland-Hodgman polygon clipping
- Symmetric difference

### T

- Take notes on the command line
- Taxicab numbers
- Terminal control/Clear the screen
- Terminal control/Coloured text
- Terminal control/Cursor movement
- Terminal control/Cursor positioning
- Terminal control/Dimensions
- Terminal control/Display an extended character
- Terminal control/Hiding the cursor
- Terminal control/Inverse video
- Terminal control/Positional read
- Terminal control/Preserve screen
- Terminal control/Ringing the terminal bell
- Terminal control/Unicode output
- Test a function
- Text processing/2
- The ISAAC Cipher
- Tic-tac-toe
- Time a function
- Tokenize a string with escaping
- Top rank per group
- Topic variable
- Topological sort
- Topswops
- Total circles area
- Truncate a file
- Twelve statements

### U

### V

- Validate International Securities Identification Number
- Vampire number
- Van der Corput sequence
- Variable-length quantity
- Variable size/Set
- Verify distribution uniformity/Chi-squared test
- Verify distribution uniformity/Naive
- Video display modes
- Vigenère cipher/Cryptanalysis
- Vogel's approximation method
- Voronoi diagram

### W

### Draft tasks without implementation[edit]

These tasks as drafts, meaning they largely need more work to turn them into full tasks. Perhaps you can help by trying to implement them in ALGOL 68 (after all, one of the key requirements for a task being non-draft is multiple implementations, preferably in widely different languages) but be aware that this may be difficult because of lack of definition of the task itself.

### A

- A* search algorithm
- ASCII art diagram converter
- Addition-chain exponentiation
- Addition chains
- Angle difference between two bearings
- Apply a digitial filter (direct form II transposed)
- Arithmetic coding/As a generalized change of radix
- Aspect Oriented Programming
- Assertions in design by contract
- AudioAlarm
- Audio Overlap Loop
- Audio frequency generator

### C

- Card shuffles
- Chebyshev coefficients
- Check input device is a terminal
- Check output device is a terminal
- Chess player
- Chess player/Move generation
- Chess player/Program options and user interface
- Chess player/Search and evaluation
- Cipolla's algorithm
- Code segment unload
- Color wheel
- Combinations with repetitions/Square Digit Chain
- Compiler/AST interpreter
- Continued fraction/Arithmetic/G(matrix NG, Contined Fraction N)
- Continued fraction/Arithmetic/G(matrix NG, Contined Fraction N1, Contined Fraction N2)
- Convex hull
- Create an object/Native demonstration
- Currency
- Cycle detection

### D

### E

### F

### I

### L

### M

### O

### P

### R

- Railway circuit
- Ramer-Douglas-Peucker line simplification
- Ramsey's theorem
- Read a file character by character/UTF8
- Readline interface
- Recursive descent parser generator
- Reflection/List methods
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Reverse the gender of a string
- Robots
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks sorted by average lines of code
- Run as a daemon or service

### S

- Sattolo cycle
- Self-hosting compiler
- Separate the house number from the street name
- Sequence of primorial primes
- Shortest common supersequence
- Simulated annealing
- Singly-linked list/Element removal
- Snake
- Snake And Ladder
- Solve a Rubik's Cube
- Solving coin problems
- Sorting Algorithms/Circle Sort
- Sorting algorithms/Cycle sort
- Sorting algorithms/Patience sort
- Sorting algorithms/Tree sort on a linked list
- Starting a web browser
- Subset sum problem
- Substitution Cipher
- Suffix tree
- Superpermutation minimisation

### T

- Table creation
- Tamagotchi emulator
- Tarjan
- Tasks without examples
- Terminal control/Restricted width positional input/No wrapping
- Terminal control/Restricted width positional input/With wrapping
- Tetris
- Text to HTML
- Time-based One-time Password Algorithm
- Tonelli-Shanks algorithm
- Topological sort/Extracted top item
- Transportation problem
- Type detection

### U

### V

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in ALGOL 68, but somebody, somewhere, decided that the example implementation was faulty or in some other way requiring attention. If you're familiar with the task and language, please consider reviewing/correcting the example and removing the notice.

### Other pages[edit]

These are other pages related to ALGOL 68 which require attention; with your knowledge and assistance, we can improve the quality of the site's content.

## Not Considered[edit]

These tasks are not generally counted toward "unimplemented", as somebody, somewhere, decided that ALGOL 68 was inappropriate for these tasks, or implementations of them would be unenlightening. Feel free to try your hand at them anyway.

## End of List[edit]

Again, feel free to try your hand at any of the tasks listed on this page.