# Reports:Tasks not implemented in Fortran

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## Contents

## Not implemented[edit]

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

### A

- ASCII art diagram converter
- Abbreviations, automatic
- Abbreviations, easy
- Abbreviations, simple
- Abelian sandpile model/Identity
- Achilles numbers
- Active Directory/Connect
- Active Directory/Search for a user
- Active object
- Additive primes
- Algebraic data types
- Almkvist-Giullera formula for pi
- Amb
- Anagrams/Deranged anagrams
- Angles (geometric), normalization and conversion
- Animation
- Apply a digital filter (direct form II transposed)
- Archimedean spiral
- Arithmetic evaluation
- Arithmetic numbers
- Assertions
- Associative array/Creation
- Associative array/Iteration
- Associative array/Merging
- Atomic updates
- Average loop length

### B

- Balanced ternary
- Base64 decode data
- Bell numbers
- Bernoulli numbers
- Best shuffle
- Bin given limits
- Binary strings
- Bioinformatics/Sequence mutation
- Bioinformatics/base count
- Bitcoin/address validation
- Bitcoin/public point to address
- Bitmap/PPM conversion through a pipe
- Bitmap/Read an image through a pipe
- Bitwise IO
- Brace expansion
- Break OO privacy
- Brilliant numbers
- Burrows–Wheeler transform

### C

- Calkin-Wilf sequence
- Canny edge detector
- Canonicalize CIDR
- Cantor set
- Casting out nines
- Catalan numbers/Pascal's triangle
- Catmull–Clark subdivision surface
- Chaocipher
- Chat server
- Check Machin-like formulas
- Check input device is a terminal
- Check output device is a terminal
- Checkpoint synchronization
- Chernick's Carmichael numbers
- Cheryl's birthday
- Chinese remainder theorem
- Chinese zodiac
- Chowla numbers
- Church numerals
- Circular primes
- Cistercian numerals
- Closures/Value capture
- Color of a screen pixel
- Color quantization
- Color wheel
- Colorful numbers
- Colour bars/Display
- Colour pinstripe/Display
- Colour pinstripe/Printer
- Combinations and permutations
- Commatizing numbers
- Compare sorting algorithms' performance
- Composite numbers k with no single digit factors whose factors are all substrings of k
- Consecutive primes with ascending or descending differences
- Continued fraction/Arithmetic/Construct from rational number
- Copy stdin to stdout
- Count the coins
- Create an object at a given address
- Cuban primes
- Cullen and Woodall numbers
- Currency
- Currying
- Curzon numbers
- Cut a rectangle
- Cyclops numbers
- Cyclotomic polynomial

### D

- DNS query
- Date manipulation
- De Bruijn sequences
- Death Star
- Deceptive numbers
- Deconvolution/2D+
- Deepcopy
- Deming's funnel
- Descending primes
- Determine if a string is collapsible
- Determine if only one instance is running
- Determine if two triangles overlap
- Determine sentence type
- Dice game probabilities
- Dijkstra's algorithm
- Dinesman's multiple-dwelling problem
- Dining philosophers
- Disarium numbers
- Display a linear combination
- Display an outline as a nested table
- Distributed programming
- Diversity prediction theorem
- Dominoes
- Dragon curve
- Draw a cuboid
- Draw a pixel
- Draw a rotating cube
- Draw a sphere
- Duffinian numbers

### E

- EKG sequence convergence
- Earliest difference between prime gaps
- Eban numbers
- Echo server
- Eertree
- Egyptian division
- Egyptian fractions
- Elementary cellular automaton
- Elementary cellular automaton/Infinite length
- Elementary cellular automaton/Random number generator
- Elliptic Curve Digital Signature Algorithm
- Elliptic curve arithmetic
- Empty directory
- Entropy/Narcissist
- Equal prime and composite sums
- Erdös-Selfridge categorization of primes
- Esthetic numbers
- Euler's constant 0.5772...
- Events
- Exceptions
- Exceptions/Catch an exception thrown in a nested call
- Executable library
- Execute Computer/Zero
- Execute SNUSP
- Execute a Markov algorithm
- Exponentiation with infix operators in (or operating on) the base

### F

- FASTA format
- FTP
- Faces from a mesh
- Factorial base numbers indexing permutations of a collection
- Factorions
- Fairshare between two and more
- Farey sequence
- Faulhaber's formula
- Faulhaber's triangle
- Fermat numbers
- Fibonacci word
- Fibonacci word/fractal
- File size distribution
- Find Chess960 starting position identifier
- Find common directory path
- Find duplicate files
- Find palindromic numbers in both binary and ternary bases
- Find the intersection of a line with a plane
- First-class functions
- First class environments
- First perfect square in base n with n unique digits
- First power of 2 that has leading decimal digits of 12
- Fivenum
- Fixed length records
- Fork
- Formal power series
- Fortunate numbers
- Four is the number of letters in the ...
- Fractal tree
- Fraction reduction
- French Republican calendar
- Function frequency
- Function prototype
- Functional coverage tree
- Fusc sequence

### G

### H

### I

- Idiomatically determine all the characters that can be used for symbols
- Idiomatically determine all the lowercase and uppercase letters
- Image convolution
- Image noise
- Imaginary base numbers
- Index finite lists of positive integers
- Inheritance/Multiple
- Intersecting number wheels
- Introspection
- Inverted index
- Iterated digits squaring

### J

### K

### L

- Lah numbers
- Largest number divisible by its digits
- Last letter-first letter
- Latin Squares in reduced form
- Latin Squares in reduced form/Randomizing using Jacobson and Matthews’ Technique
- Legendre prime counting function
- Levenshtein distance/Alignment
- List rooted trees
- Long literals, with continuations
- Long primes
- Longest increasing subsequence
- Longest string challenge
- Loops/With multiple ranges
- Loops/Wrong ranges
- Lucky and even lucky numbers

### M

- MAC vendor lookup
- MD4
- MD5/Implementation
- Machine code
- Magic constant
- Magic squares of doubly even order
- Magic squares of singly even order
- Magnanimous numbers
- Main step of GOST 28147-89
- Make directory path
- Mastermind
- Matrix digital rain
- Mayan numerals
- Maze generation
- Maze solving
- McNuggets problem
- Median filter
- Merge and aggregate datasets
- Metallic ratios
- Metaprogramming
- Metered concurrency
- Metronome
- Mian-Chowla sequence
- Mind boggling card trick
- Minesweeper game
- Minimal steps down to 1
- Minimum multiple of m where digital sum equals m
- Minimum positive multiple in base 10 using only 0 and 1
- Minkowski question-mark function
- Modified random distribution
- Modular arithmetic
- Modular exponentiation
- Modular inverse
- Monads/List monad
- Monads/Maybe monad
- Monads/Writer monad
- Morse code
- Motzkin numbers
- Mouse position
- Move-to-front algorithm
- Multi-base primes
- Multiplicative order
- Multisplit
- Munching squares
- Musical scale
- Mutex

### N

- N-smooth numbers
- Narcissist
- Narcissistic decimal number
- Nautical bell
- Negative base numbers
- Nested templated data
- Next highest int from digits
- Nim game
- Non-continuous subsequences
- Non-transitive dice
- Nonoblock
- Nonogram solver
- Null object
- Numbers which are not the sum of distinct squares
- Numerical and alphabetical suffixes

### O

### P

- P-Adic numbers, basic
- P-Adic square roots
- P-value correction
- Padovan n-step number sequences
- Padovan sequence
- Palindrome dates
- Palindromic gapful numbers
- Pancake numbers
- Paraffins
- Parallel brute force
- Parameterized SQL statement
- Parse an IP Address
- Parsing/RPN to infix conversion
- Partial function application
- Particle fountain
- Partition an integer x into n primes
- Partition function P
- Pascal's triangle/Puzzle
- Password generator
- Peano curve
- Pell's equation
- Pell numbers
- Penney's game
- Pentagram
- Pentomino tiling
- Percolation/Bond percolation
- Percolation/Mean cluster density
- Perfect totient numbers
- Periodic table
- Peripheral drift illusion
- Permutation test
- Permutations/Derangements
- Permutations/Rank of a permutation
- Permutations by swapping
- Pierpont primes
- Pig the dice game
- Pig the dice game/Player
- Pinstripe/Display
- Pinstripe/Printer
- Pisano period
- Plasma effect
- Play recorded sounds
- Playfair cipher
- Plot coordinate pairs
- Poker hand analyser
- Polyspiral
- Power set
- Pragmatic directives
- Primality by Wilson's theorem
- Prime triangle
- Primes - allocate descendants to their ancestors
- Pseudo-random numbers/Combined recursive generator MRG32k3a
- Pseudo-random numbers/Middle-square method
- Pseudo-random numbers/PCG32
- Pseudo-random numbers/Splitmix64
- Pseudo-random numbers/Xorshift star
- Pythagoras tree
- Pythagorean quadruples

### R

- RCRPG
- RIPEMD-160
- RPG attributes generator
- RSA code
- Ramanujan's constant
- Ramanujan primes/twins
- Ramer-Douglas-Peucker line simplification
- Random Latin squares
- Random sentence from book
- Range consolidation
- Ranking methods
- Rare numbers
- Read a file character by character/UTF8
- Recaman's sequence
- Record sound
- Reflection/Get source
- Reflection/List methods
- Regular expressions
- Rendezvous
- Rep-string
- Repeat
- Repunit primes
- Resistor mesh
- Respond to an unknown method call
- Retrieve and search chat history
- Rhonda numbers
- Rosetta Code/Count examples
- Rosetta Code/Find bare lang tags
- Rosetta Code/Find unimplemented tasks
- Rosetta Code/Fix code tags
- Rosetta Code/Rank languages by number of users
- Rosetta Code/Rank languages by popularity
- Runtime evaluation
- Runtime evaluation/In an environment
- Ruth-Aaron numbers

### S

- S-expressions
- SHA-256 Merkle tree
- SOAP
- SQL-based authentication
- Safe addition
- Safe primes and unsafe primes
- Sailors, coconuts and a monkey problem
- Same fringe
- Scope/Function names and labels
- Scope modifiers
- Search in paragraph's text
- Selectively replace multiple instances of a character within a string
- Self-describing numbers
- Self numbers
- Semiprime
- Send an unknown method call
- Sequence: nth number with exactly n divisors
- Sequence: smallest number greater than previous term with exactly n divisors
- Sequence: smallest number with exactly n divisors
- Set
- Set consolidation
- Set of real numbers
- Set puzzle
- Set right-adjacent bits
- Sexy primes
- Shortest common supersequence
- Sierpinski arrowhead curve
- Sierpinski pentagon
- Sierpinski square curve
- Sierpinski triangle/Graphical
- Simple database
- Simple turtle graphics
- Simple windowed application
- Simulate input/Keyboard
- Simulate input/Mouse
- Singleton
- Sleeping Beauty problem
- Smallest number k such that k+2^m is composite for all m less than k
- Smarandache prime-digital sequence
- Snake
- Sockets
- Sokoban
- Solve a Hidato puzzle
- Solve a Holy Knight's tour
- Solve a Hopido puzzle
- Solve a Numbrix puzzle
- Sort a list of object identifiers
- Sort an outline at every level
- Sort numbers lexicographically
- Sorting algorithms/Cocktail sort with shifting bounds
- Sorting algorithms/Permutation sort
- Sorting algorithms/Strand sort
- Soundex
- Sparkline in unicode
- Speech synthesis
- Spelling of ordinal numbers
- Spinning rod animation/Text
- Square-free integers
- Square but not cube
- Square form factorization
- Stable marriage problem
- Start from a main routine
- State name puzzle
- Stirling numbers of the first kind
- Stirling numbers of the second kind
- Straddling checkerboard
- Strassen's algorithm
- Strong and weak primes
- Successive prime differences
- Sudan function
- Suffixation of decimal numbers
- Sum and product puzzle
- Sum of elements below main diagonal of matrix
- Summarize and say sequence
- Summarize primes
- Super-d numbers
- Superellipse
- Superpermutation minimisation
- Sylvester's sequence
- Synchronous concurrency

### T

- Table creation/Postal addresses
- Tarjan
- Tau function
- Tau number
- Teacup rim text
- Terminal control/Cursor movement
- 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
- Textonyms
- The Name Game
- Thiele's interpolation formula
- Tonelli-Shanks algorithm
- Topic variable
- Total circles area
- Totient function
- Tree datastructures
- Tree from nesting levels
- Truth table
- Twelve statements
- Twin primes
- Two's complement
- Two bullet roulette

### U

### V

### W

- Walk a directory/Non-recursively
- Walk a directory/Recursively
- War card game
- Water collected between towers
- Web scraping
- Weird numbers
- Wieferich primes
- Wilson primes of order n
- Window creation
- Window creation/X11
- Window management
- Word frequency
- Word ladder
- Word search
- Word wheel
- Wordiff
- World Cup group stage
- Write language name in 3D ASCII
- Write to Windows event log

### 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 Fortran (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
- ABC words
- ADFGVX cipher
- Addition-chain exponentiation
- Addition chains
- Air mass
- Alternade words
- Anadromes
- Anagram generator
- Append numbers at same position in strings
- Arithmetic coding/As a generalized change of radix
- Arithmetic derivative
- Aspect oriented programming
- Audio alarm
- Audio frequency generator
- Audio overlap loop
- Autogram checker

### B

- B-spline
- Babylonian spiral
- Bacon cipher
- Banker's algorithm
- Base58Check encoding
- Base64 encode data
- Base 16 numbers needing a to f
- Bifid cipher
- Bilinear interpolation
- Binary coded decimal
- Bioinformatics/Global alignment
- Bioinformatics/Subsequence
- Birthday problem
- Black box
- Blackjack strategy
- Boids
- Boyer-Moore string search
- Brace expansion using ranges

### C

- CLI-based maze-game
- Camel case and snake case
- Card shuffles
- Change e letters to i in words
- Changeable words
- Chebyshev coefficients
- Checksumcolor
- Chemical calculator
- Chess player
- Cipolla's algorithm
- Code Golf: Code Golf
- Code segment unload
- Collect and sort square numbers in ascending order from three lists
- Combinations with repetitions/Square digit chain
- Common list elements
- Common sorted list
- Compiler/Preprocessor
- Compiler/Simple file inclusion pre processor
- Compiler/Verifying syntax
- Concatenate two primes is also prime
- Conjugate a Latin verb
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n)
- Continued fraction/Arithmetic/G(matrix ng, continued fraction n1, continued fraction n2)
- Coprime triplets
- Coprimes
- Count how many vowels and consonants occur in a string
- Count the coins/0-1
- Cousin primes
- Create an executable for a program in an interpreted language
- Create an object/Native demonstration
- Create your own text control codes
- Cross compilation
- Cubic special primes
- Curve that touches three points
- Cycle detection
- Cycles of a permutation

### D

- Data Encryption Standard
- Dating agency
- Day of the week of Christmas and New Year
- Days between dates
- Decision tables
- Digit fifth powers
- Diophantine linear system solving
- Discrete Fourier transform
- Distinct palindromes within decimal numbers
- Distinct power numbers
- Distribution of 0 digits in factorial series
- Divide a rectangle into a number of unequal triangles
- Doomsday rule
- Doubly-linked list/Element removal
- Draw pixel 2

### E

### F

- Factorial primes
- Fibonacci heap
- Fibonacci matrix-exponentiation
- Find URI in text
- Find adjacent primes which differ by a square integer
- Find first missing positive
- Find minimum number of coins that make a given value
- Find prime n such that reversed n is also prime
- Find prime numbers of the form n*n*n+2
- Find square difference
- Find squares n where n+1 is prime
- Find words which contain the most consonants
- Find words which contains all the vowels
- Find words which contains more than 3 e vowels
- Find words whose first and last three letters are equal
- Find words with alternating vowels and consonants
- Finite state machine
- First 9 prime Fibonacci number
- Four sides of square
- Free polyominoes enumeration
- Frobenius numbers

### G

### I

### L

- Largest difference between adjacent primes
- Largest five adjacent number
- Largest palindrome product
- Largest prime factor
- Largest product in a grid
- Last list item
- Launch rocket with countdown and acceleration in stdout
- Line circle intersection
- Logistic curve fitting in epidemiology
- Long stairs
- Longest common prefix
- Longest common suffix
- Longest palindromic substrings
- Longest substrings without repeating characters

### M

- Make a backup file
- Marching squares
- Markov chain text generator
- Maximum difference between adjacent elements of list
- Minimum number of cells after, before, above and below NxN squares
- Minimum numbers of three lists
- Minimum primes
- Modulinos
- Montgomery reduction
- Morpion solitaire
- Mosaic matrix
- Most frequent k chars distance
- Multidimensional Newton-Raphson method
- Multiline shebang
- Multiton

### N

- N-queens minimum and knights and bishops
- NYSIIS
- Names to numbers
- Native shebang
- Neighbour primes
- Next special primes
- Nice primes
- Nimber arithmetic
- Number triplets game
- Numbers divisible by their individual digits, but not by the product of their digits.
- Numbers in base-16 representation that cannot be written with decimal digits
- Numbers in base 10 that are palindromic in bases 2, 4, and 16
- Numbers which binary and ternary digit sum are prime
- Numbers whose count of divisors is prime
- Numbers with prime digits whose sum is 13
- Numbers with same digit set in base 10 and base 16
- Numeric separator syntax
- Numerical integration/Adaptive Simpson's method

### O

### P

- Palindromic primes
- Palindromic primes in base 16
- Pan base non-primes
- Pandigital prime
- Parse EBNF
- Parse command-line arguments
- Particle swarm optimization
- Penrose tiling
- Perceptron
- Permutations with repetitions
- Permutations with some identical elements
- Permuted multiples
- Piprimes
- Polynomial derivative
- Polynomial synthetic division
- Positive decimal integers with the digit 1 occurring exactly twice
- Powerful numbers
- Practical numbers
- Price list behind API
- Prime numbers p for which the sum of primes less than or equal to p is prime
- Prime numbers which contain 123
- Prime triplets
- Prime words
- Primes which contain only one odd digit
- Primes whose first and last number is 3
- Primes whose sum of digits is 25
- Primes with digits in nondecreasing order
- Print debugging statement
- Print itself
- Process SMIL directives in XML data
- Pseudorandom number generator image

### R

- Railway circuit
- Ramanujan primes
- Ramsey's theorem
- Range modifications
- Raster bars
- Readline interface
- Recursive descent parser generator
- Red black tree sort
- Remote agent/Agent interface
- Remote agent/Agent logic
- Remote agent/Simulation
- Resistance calculator
- Resistance network calculator
- Reverse the gender of a string
- Reverse the order of lines in a text file while preserving the contents of each line
- Robots
- 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
- Sattolo cycle
- Segmentation fault protection
- Self-hosting compiler
- Separate the house number from the street name
- Shift list elements to left by 3
- Show the (decimal) value of a number of 1s appended with a 3, then squared
- Sierpinski curve
- Sine wave
- Smallest enclosing circle problem
- Smallest multiple
- Smallest numbers
- Smallest power of 6 whose decimal expansion contains n
- Smallest square that begins with n
- Snake and ladder
- Solve a Rubik's cube
- Solve equations with substitution method
- Solve hanging lantern problem
- Solve triangle solitare puzzle
- Solving coin problems
- Sort primes from list to a list
- Sort the letters of string in alphabetical order
- Sorting algorithms/Cycle sort
- Sorting algorithms/Tree sort on a linked list
- Special divisors
- Special factorials
- Special neighbor primes
- Special pythagorean triplet
- Spoof game
- Square root by hand
- Starting a web browser
- Steady squares
- Strange numbers
- Strange plus numbers
- Strange unique prime triplets
- Subset sum problem
- Substring primes
- Suffix tree
- Sum data type
- Sum of first n cubes
- Sum of primes in odd positions is prime
- Sum of square and cube digits of an integer are primes
- Sum of the digits of n is substring of n
- Sum of two adjacent numbers are primes
- Summation of primes
- Sunflower fractal

### T

- Table creation
- Tamagotchi emulator
- Terminal control/Restricted width positional input/No wrapping
- Terminal control/Restricted width positional input/With wrapping
- Tetris
- Text between
- Text completion
- Text to HTML
- The ISAAC cipher
- Three word location
- Time-based one-time password algorithm
- Topological sort/Extracted top item
- Transliterate English text using the Greek alphabet
- Transportation problem
- Triplet of three numbers
- Tropical algebra overloading

### U

### W

## Requiring Attention[edit]

### Examples[edit]

These tasks have implementations in Fortran, 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.

### No pages found.

### Other pages[edit]

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

### G

## Not Considered[edit]

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