78,961
students have developed their C skills on Exercism.

Students
78,961
Submissions
628,101
Mentoring Discussions
7,005

The C track needs attention ⚠️

Building

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Use your knowledge to build the C track itself

Build Test Runners

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Create Test Runners that have the single responsibility of taking a solution, running all tests and returning a standardized output.

Usage statistics

Total Test Runner Runs
584,304
Test Run Pass Rate
12.6% (73705)
Test Run Fail Rate
19.3% (113033)
Test Run Error Rate
68.0% (397566)

Build Analyzers

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Build an Analyzer for C: Exercism's analyzers automatically assess student's submissions and provide mentor-style commentary.

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Build Representers

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Build a Representer: a bit of code that has the single responsibility of taking a solution and returning a normalized representation of it.

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Create Practice Exercises

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Practice Exercises are exercises designed to allow students to solve an arbitrary problem, with the aim of them making use of the concepts they have learned so far.

Next goal: Implement 130 practice exercises. Find out more.

Usage statistics

73 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
55,538
207,971 (avg. 3.7)
22,546 (40.6%)
20 (0.0%)
Armstrong Numbers Armstrong Numbers
15,576
82,918 (avg. 5.3)
6,554 (42.1%)
1,499 (9.6%)
Isogram Isogram
6,968
59,851 (avg. 8.6)
3,901 (56.0%)
1,332 (19.1%)
Hamming Hamming
3,571
16,343 (avg. 4.6)
2,887 (80.8%)
534 (15.0%)
Grains Grains
3,113
20,732 (avg. 6.7)
2,469 (79.3%)
418 (13.4%)
Difference of Squares Difference of Squares
2,611
11,147 (avg. 4.3)
2,214 (84.8%)
295 (11.3%)
Square Root Square Root
2,185
8,116 (avg. 3.7)
1,477 (67.6%)
198 (9.1%)
Grade School Grade School
1,730
16,680 (avg. 9.6)
721 (41.7%)
140 (8.1%)
Binary Search Binary Search
1,978
16,035 (avg. 8.1)
1,308 (66.1%)
178 (9.0%)
Rational Numbers Rational Numbers
898
7,588 (avg. 8.4)
541 (60.2%)
75 (8.4%)
Circular Buffer Circular Buffer
1,078
8,686 (avg. 8.1)
519 (48.1%)
75 (7.0%)
List Ops List Ops
956
6,566 (avg. 6.9)
514 (53.8%)
63 (6.6%)
Reverse String Reverse String
419
3,614 (avg. 8.6)
315 (75.2%)
17 (4.1%)
Resistor Color Resistor Color
5,596
33,751 (avg. 6.0)
2,780 (49.7%)
626 (11.2%)
Pythagorean Triplet Pythagorean Triplet
757
3,640 (avg. 4.8)
362 (47.8%)
38 (5.0%)
Saddle Points Saddle Points
552
2,917 (avg. 5.3)
307 (55.6%)
31 (5.6%)
Allergies Allergies
727
2,746 (avg. 3.8)
491 (67.5%)
40 (5.5%)
Phone Number Phone Number
619
4,245 (avg. 6.9)
391 (63.2%)
42 (6.8%)
Clock Clock
728
3,375 (avg. 4.6)
445 (61.1%)
36 (4.9%)
Sieve Sieve
672
2,922 (avg. 4.3)
475 (70.7%)
33 (4.9%)
Robot Simulator Robot Simulator
708
2,182 (avg. 3.1)
468 (66.1%)
39 (5.5%)
Pascal's Triangle Pascal's Triangle
597
2,223 (avg. 3.7)
368 (61.6%)
34 (5.7%)
Binary Binary
801
5,063 (avg. 6.3)
610 (76.2%)
41 (5.1%)
Queen Attack Queen Attack
482
1,580 (avg. 3.3)
367 (76.1%)
28 (5.8%)
Linked List Linked List
801
5,230 (avg. 6.5)
410 (51.2%)
73 (9.1%)
Darts Darts
1,897
3,696 (avg. 1.9)
1,303 (68.7%)
70 (3.7%)
Resistor Color Duo Resistor Color Duo
1,119
1,967 (avg. 1.8)
831 (74.3%)
19 (1.7%)
Resistor Color Trio Resistor Color Trio
937
2,342 (avg. 2.5)
686 (73.2%)
19 (2.0%)
Acronym Acronym
1,880
6,937 (avg. 3.7)
1,233 (65.6%)
109 (5.8%)
Gigasecond Gigasecond
1,266
1,731 (avg. 1.4)
932 (73.6%)
131 (10.3%)
Space Age Space Age
961
2,107 (avg. 2.2)
726 (75.5%)
22 (2.3%)
High Scores High Scores
168
1,053 (avg. 6.3)
125 (74.4%)
7 (4.2%)
Pangram Pangram
1,184
3,817 (avg. 3.2)
874 (73.8%)
44 (3.7%)
Word Count Word Count
1,460
2,805 (avg. 1.9)
668 (45.8%)
190 (13.0%)
Rail Fence Cipher Rail Fence Cipher
310
1,343 (avg. 4.3)
200 (64.5%)
8 (2.6%)
Matching Brackets Matching Brackets
613
1,993 (avg. 3.3)
409 (66.7%)
51 (8.3%)
Nucleotide Count Nucleotide Count
705
3,571 (avg. 5.1)
499 (70.8%)
19 (2.7%)
RNA Transcription RNA Transcription
788
2,310 (avg. 2.9)
589 (74.7%)
33 (4.2%)
Secret Handshake Secret Handshake
427
2,112 (avg. 4.9)
291 (68.1%)
15 (3.5%)
Meetup Meetup
596
874 (avg. 1.5)
305 (51.2%)
9 (1.5%)
Pig Latin Pig Latin
274
1,595 (avg. 5.8)
168 (61.3%)
8 (2.9%)
Leap Leap
1,054
2,495 (avg. 2.4)
855 (81.1%)
21 (2.0%)
Two Fer Two Fer
471
1,424 (avg. 3.0)
365 (77.5%)
13 (2.8%)
Beer Song Beer Song
675
2,235 (avg. 3.3)
433 (64.1%)
112 (16.6%)
Raindrops Raindrops
662
1,495 (avg. 2.3)
513 (77.5%)
19 (2.9%)
Roman Numerals Roman Numerals
737
10,927 (avg. 14.8)
475 (64.5%)
67 (9.1%)
Wordy Wordy
267
1,072 (avg. 4.0)
163 (61.0%)
11 (4.1%)
Bob Bob
633
2,627 (avg. 4.2)
449 (70.9%)
17 (2.7%)
Complex Numbers Complex Numbers
364
914 (avg. 2.5)
274 (75.3%)
3 (0.8%)
Sum of Multiples Sum of Multiples
528
1,225 (avg. 2.3)
337 (63.8%)
9 (1.7%)
Two Bucket Two Bucket
167
477 (avg. 2.9)
97 (58.1%)
0 (0.0%)
Anagram Anagram
518
1,431 (avg. 2.8)
337 (65.1%)
14 (2.7%)
Binary Search Tree Binary Search Tree
405
1,758 (avg. 4.3)
212 (52.3%)
29 (7.2%)
Say Say
219
781 (avg. 3.6)
118 (53.9%)
3 (1.4%)
ETL ETL
284
1,108 (avg. 3.9)
181 (63.7%)
7 (2.5%)
Series Series
389
1,400 (avg. 3.6)
235 (60.4%)
4 (1.0%)
Diamond Diamond
273
942 (avg. 3.5)
176 (64.5%)
6 (2.2%)
Minesweeper Minesweeper
281
922 (avg. 3.3)
155 (55.2%)
6 (2.1%)
Run-Length Encoding Run-Length Encoding
254
1,110 (avg. 4.4)
146 (57.5%)
7 (2.8%)
Atbash Cipher Atbash Cipher
353
1,147 (avg. 3.2)
234 (66.3%)
30 (8.5%)
Crypto Square Crypto Square
216
766 (avg. 3.5)
130 (60.2%)
0 (0.0%)
React React
568
2,510 (avg. 4.4)
129 (22.7%)
18 (3.2%)
Prime Factors Prime Factors
310
772 (avg. 2.5)
198 (63.9%)
4 (1.3%)
Nth Prime Nth Prime
382
1,060 (avg. 2.8)
238 (62.3%)
5 (1.3%)
Perfect Numbers Perfect Numbers
317
957 (avg. 3.0)
228 (71.9%)
2 (0.6%)
Triangle Triangle
461
1,751 (avg. 3.8)
289 (62.7%)
8 (1.7%)
Collatz Conjecture Collatz Conjecture
404
1,291 (avg. 3.2)
314 (77.7%)
25 (6.2%)
Luhn Luhn
326
1,960 (avg. 6.0)
212 (65.0%)
14 (4.3%)
Palindrome Products Palindrome Products
279
1,022 (avg. 3.7)
142 (50.9%)
11 (3.9%)
All Your Base All Your Base
338
1,081 (avg. 3.2)
180 (53.3%)
6 (1.8%)
Scrabble Score Scrabble Score
306
969 (avg. 3.2)
217 (70.9%)
16 (5.2%)
Sublist Sublist
267
879 (avg. 3.3)
150 (56.2%)
8 (3.0%)
Largest Series Product Largest Series Product
310
1,219 (avg. 3.9)
199 (64.2%)
4 (1.3%)
57 unimplemented practice exercises
Affine Cipher Affine Cipher
Alphametics Alphametics
Bank Account Bank Account
Book Store Book Store
Bottle Song Bottle Song
Bowling Bowling
Change Change
Connect Connect
Custom Set Custom Set
D&D Character D&D Character
DOT DSL DOT DSL
Dominoes Dominoes
Error Handling Error Handling
Flatten Array Flatten Array
Food Chain Food Chain
Forth Forth
Go Counting Go Counting
Grep Grep
Hangman Hangman
House House
ISBN Verifier ISBN Verifier
Killer Sudoku Helper Killer Sudoku Helper
Kindergarten Garden Kindergarten Garden
Knapsack Knapsack
Ledger Ledger
Lens Person Lens Person
Markdown Markdown
Matrix Matrix
Micro Blog Micro Blog
OCR Numbers OCR Numbers
POV POV
PaaS I/O PaaS I/O
Parallel Letter Frequency Parallel Letter Frequency
Poker Poker
Protein Translation Protein Translation
Proverb Proverb
REST API REST API
Rectangles Rectangles
Robot Name Robot Name
Rotational Cipher Rotational Cipher
SGF Parsing SGF Parsing
Satellite Satellite
Scale Generator Scale Generator
Simple Cipher Simple Cipher
Simple Linked List Simple Linked List
Spiral Matrix Spiral Matrix
State of Tic-Tac-Toe State of Tic-Tac-Toe
Strain Strain
Tournament Tournament
Transpose Transpose
Tree Building Tree Building
Twelve Days Twelve Days
Variable Length Quantity Variable Length Quantity
Word Search Word Search
Yacht Yacht
Zebra Puzzle Zebra Puzzle
Zipper Zipper