# 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.

### B

### C

### D

### F

### 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
- Parameterized SQL statement
- Particle fountain
- Peaceful chess queen armies
- Pentomino tiling
- Percolation/Bond percolation
- Peripheral drift illusion
- Pinstripe/Printer
- Pisano period
- Play recorded sounds
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/Splitmix64
- Pseudo-random numbers/Xorshift star

### R

### S

- SHA-256 Merkle tree
- SOAP
- SQL-based authentication
- Secure temporary file
- Self numbers
- Send email
- Shortest common supersequence
- Sierpinski arrowhead curve
- Sierpinski pentagon
- Simulate input/Keyboard
- Simulate input/Mouse
- Smallest number k such that k+2^m is composite for all m less than k
- Sokoban
- Solve a Hidato puzzle
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Sorting algorithms/Cocktail sort with shifting bounds
- Speech synthesis
- Spinning rod animation/Text
- Strassen's algorithm
- Stream merge
- Suffixation of decimal numbers
- Sum and product puzzle
- Sylvester's sequence

### 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
- Camel case and snake case
- Checksumcolor
- Chemical calculator
- Chess player
- Code segment unload
- Collect and sort square numbers in ascending order from three lists
- Combinations with repetitions/Square digit chain
- Compiler/Preprocessor
- Compiler/Verifying syntax
- Concatenate two primes is also prime
- Conjugate a Latin verb
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n1, continued fraction n2)
- Coprime triplets
- Create your own text control codes
- Cubic special primes
- Cycles of a permutation

### D

### E

### F

### G

### I

### L

### M

### N

### P

- Palindromic primes
- Palindromic primes in base 16
- Pandigital prime
- Parse EBNF
- Perceptron
- Permuted multiples
- Polynomial derivative
- Powerful numbers
- Price list behind API
- Prime triplets
- Primes which contain only one odd digit
- Primes whose first and last number is 3
- Primes whose sum of digits is 25
- Print itself
- Process SMIL directives in XML data
- Pseudorandom number generator image

### R

- Ramanujan primes
- Range modifications
- Raster bars
- Readline interface
- Red black tree sort
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Remove vowels from a string
- Resistance calculator
- Resistance network calculator
- Rodrigues’ rotation formula
- Rosetta Code/List authors of task descriptions
- Rosetta Code/Run examples
- Rosetta Code/Tasks without examples
- Round-robin tournament schedule
- Run as a daemon or service

### S

- Safe and Sophie Germain primes
- Safe mode
- Sanitize user input
- Segmentation fault protection
- Shift list elements to left by 3
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Sierpinski curve
- Singly-linked list/Element removal
- Smallest enclosing circle problem
- Smallest multiple
- Smallest power of 6 whose decimal expansion contains n
- Solve a Rubik's cube
- Solve equations with substitution method
- Solving coin problems
- Special factorials
- Special neighbor primes
- Special pythagorean triplet
- Spoof game
- Square root by hand
- Strange unique prime triplets
- Substring primes
- Sum data type
- Sum of divisors
- Sum of primes in odd positions is prime
- Summation of primes

### T

### U

### V

### 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.