# Reports:Tasks not implemented in J

**Awareness**

If

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

## Contents

## Not implemented[edit]

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

### A

### B

### C

- Canonicalize CIDR
- Chaocipher
- Chat server
- Check input device is a terminal
- Chernick's Carmichael numbers
- Church numerals
- Color of a screen pixel
- Color wheel
- Colour pinstripe/Printer
- Compiler/AST interpreter
- Compiler/code generator
- Compiler/lexical analyzer
- Compiler/syntax analyzer
- Compiler/virtual machine interpreter
- Copy stdin to stdout
- Create a file on magnetic tape
- Create an object at a given address
- Cyclotomic polynomial

### D

### I

### K

### M

### N

### P

- P-Adic numbers, basic
- P-Adic square roots
- P-value correction
- Padovan n-step number sequences
- Palindrome dates
- Pancake numbers
- Parallel brute force
- Parametrized SQL statement
- Partition function P
- Peaceful chess queen armies
- Percolation/Bond percolation
- Pierpont primes
- Pinstripe/Printer
- Play recorded sounds
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/PCG32
- Pseudo-random numbers/Xorshift star

### R

### S

- SHA-256 Merkle tree
- SOAP
- SQL-based authentication
- Secure temporary file
- Self numbers
- Send email
- Sequence: nth number with exactly n divisors
- Sexy primes
- Shortest common supersequence
- Sierpinski pentagon
- Simulate input/Keyboard
- Simulate input/Mouse
- Sokoban
- Solve a Hidato puzzle
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Sort an outline at every level
- Sorting algorithms/Cocktail sort with shifting bounds
- Sorting algorithms/Sleep sort
- Speech synthesis
- Spelling of ordinal numbers
- Spinning rod animation/Text
- Square Form Factorization
- Stream merge
- Suffixation of decimal numbers
- Sum and product puzzle
- Sunflower fractal

### T

### Draft tasks without implementation[edit]

These tasks are drafts, meaning they largely need more work to turn them into full tasks. Perhaps you can help by trying to implement them in J (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

### B

### C

- CLI-based maze-game
- Change e letters to i in words
- Changeable words
- Checksumcolor
- Chemical calculator
- Chess player
- Code segment unload
- Combinations with repetitions/Square digit chain
- Common list elements
- Compiler/Verifying syntax
- Consecutive Primes With Ascending Or Descending Differences
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n1, continued fraction n2)
- Count the coins/0-1
- Cubic Special Primes

### D

### F

- Fibonacci heap
- Fibonacci matrix-exponentiation
- Find URI in text
- Find first missing positive
- Find if a point is within a triangle
- Find prime n for that reversed n is also prime
- Find prime numbers of the form n*n*n+2
- Find words which contains all the vowels
- Find words which contains more than 3 e vowels
- Find words which contains most consonants
- Find words which first and last three letters are equals
- Find words with alternating vowels and consonants
- Finite state machine
- French Republican calendar

### G

### L

### M

### N

### P

- Palindromic primes
- Parse EBNF
- Penrose tiling
- Pentomino tiling
- Perceptron
- Permutations with some identical elements
- Pisano period
- Powerful numbers
- Price list behind API
- Prime words
- Primes which sum of digits is 25
- Primes with digits in nondecreasing order
- Print debugging statement
- Print itself
- Process SMIL directives in XML data
- Product of divisors
- Pseudo-random numbers/Splitmix64
- Pseudorandom number generator image

### R

- Railway circuit
- Range modifications
- Raster bars
- Readline interface
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Remove vowels from a string
- Resistance calculator
- Resistance network calculator
- Robots
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks without examples
- Run as a daemon or service

### S

- Safe mode
- Selective file copy
- Shift list elements to left by 3
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Sierpinski arrowhead curve
- Sierpinski curve
- Sierpinski square curve
- Sine wave
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Snake
- Solve a Rubik's Cube
- Solving coin problems
- Special Divisors
- Special factorials
- Spoof game
- Square root by hand
- Starting a web browser
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- Strassen's algorithm
- Substring primes
- Sum data type
- Sum of divisors

### T

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in J, 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 J which require attention; with your knowledge and assistance, we can improve the quality of the site's content.

### No pages found.

## Not Considered[edit]

These tasks are not generally counted toward "unimplemented", as somebody, somewhere, decided that J 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.