66,971
students have developed their C skills on Exercism.

Students
66,971
Submissions
476,337
Mentoring Discussions
6,511

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
433,956
Test Run Pass Rate
12.3% (53424)
Test Run Fail Rate
19.0% (82444)
Test Run Error Rate
68.7% (298088)

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

71 active practice exercises
Started
Attempts
Completions
Mentoring requests
Hello World Hello World
44,851
163,423 (avg. 3.6)
17,993 (40.1%)
20 (0.0%)
Armstrong Numbers Armstrong Numbers
12,235
62,710 (avg. 5.1)
5,275 (43.1%)
1,344 (11.0%)
Isogram Isogram
5,432
40,125 (avg. 7.4)
3,176 (58.5%)
1,262 (23.2%)
Hamming Hamming
2,666
11,282 (avg. 4.2)
2,187 (82.0%)
497 (18.6%)
Grains Grains
2,323
14,082 (avg. 6.1)
1,845 (79.4%)
387 (16.7%)
Difference of Squares Difference of Squares
1,961
7,915 (avg. 4.0)
1,643 (83.8%)
277 (14.1%)
Square Root Square Root
1,638
5,813 (avg. 3.5)
1,091 (66.6%)
182 (11.1%)
Grade School Grade School
1,241
11,327 (avg. 9.1)
531 (42.8%)
120 (9.7%)
Binary Search Binary Search
1,545
11,730 (avg. 7.6)
995 (64.4%)
168 (10.9%)
Rational Numbers Rational Numbers
688
5,272 (avg. 7.7)
411 (59.7%)
70 (10.2%)
Circular Buffer Circular Buffer
827
6,438 (avg. 7.8)
386 (46.7%)
60 (7.3%)
List Ops List Ops
732
4,804 (avg. 6.6)
375 (51.2%)
51 (7.0%)
Resistor Color Resistor Color
5,376
32,197 (avg. 6.0)
2,616 (48.7%)
623 (11.6%)
Pythagorean Triplet Pythagorean Triplet
579
2,550 (avg. 4.4)
266 (45.9%)
34 (5.9%)
Saddle Points Saddle Points
428
2,092 (avg. 4.9)
231 (54.0%)
26 (6.1%)
Allergies Allergies
520
1,649 (avg. 3.2)
337 (64.8%)
37 (7.1%)
Phone Number Phone Number
484
3,055 (avg. 6.3)
298 (61.6%)
34 (7.0%)
Clock Clock
572
2,553 (avg. 4.5)
338 (59.1%)
33 (5.8%)
Sieve Sieve
539
2,405 (avg. 4.5)
365 (67.7%)
29 (5.4%)
Robot Simulator Robot Simulator
559
1,651 (avg. 3.0)
360 (64.4%)
30 (5.4%)
Pascal's Triangle Pascal's Triangle
481
1,779 (avg. 3.7)
288 (59.9%)
26 (5.4%)
Binary Binary
632
3,990 (avg. 6.3)
473 (74.8%)
31 (4.9%)
Queen Attack Queen Attack
385
1,210 (avg. 3.1)
288 (74.8%)
25 (6.5%)
Linked List Linked List
641
3,838 (avg. 6.0)
323 (50.4%)
64 (10.0%)
Darts Darts
1,778
3,187 (avg. 1.8)
1,211 (68.1%)
69 (3.9%)
Resistor Color Duo Resistor Color Duo
1,016
1,630 (avg. 1.6)
750 (73.8%)
16 (1.6%)
Resistor Color Trio Resistor Color Trio
859
2,129 (avg. 2.5)
621 (72.3%)
18 (2.1%)
Acronym Acronym
1,767
6,073 (avg. 3.4)
1,145 (64.8%)
102 (5.8%)
Gigasecond Gigasecond
1,187
1,609 (avg. 1.4)
860 (72.5%)
129 (10.9%)
Space Age Space Age
864
1,812 (avg. 2.1)
646 (74.8%)
22 (2.5%)
Pangram Pangram
1,072
3,060 (avg. 2.9)
779 (72.7%)
39 (3.6%)
Word Count Word Count
1,372
2,535 (avg. 1.8)
618 (45.0%)
184 (13.4%)
Rail Fence Cipher Rail Fence Cipher
245
1,127 (avg. 4.6)
151 (61.6%)
7 (2.9%)
Matching Brackets Matching Brackets
536
1,452 (avg. 2.7)
351 (65.5%)
51 (9.5%)
Nucleotide Count Nucleotide Count
628
2,966 (avg. 4.7)
432 (68.8%)
15 (2.4%)
RNA Transcription RNA Transcription
702
2,019 (avg. 2.9)
514 (73.2%)
32 (4.6%)
Secret Handshake Secret Handshake
343
1,670 (avg. 4.9)
224 (65.3%)
10 (2.9%)
Meetup Meetup
539
767 (avg. 1.4)
264 (49.0%)
8 (1.5%)
Pig Latin Pig Latin
221
1,347 (avg. 6.1)
131 (59.3%)
8 (3.6%)
Leap Leap
925
2,065 (avg. 2.2)
742 (80.2%)
16 (1.7%)
Two Fer Two Fer
374
1,110 (avg. 3.0)
286 (76.5%)
12 (3.2%)
Beer Song Beer Song
603
1,951 (avg. 3.2)
391 (64.8%)
112 (18.6%)
Raindrops Raindrops
598
1,310 (avg. 2.2)
460 (76.9%)
19 (3.2%)
Roman Numerals Roman Numerals
622
7,256 (avg. 11.7)
392 (63.0%)
64 (10.3%)
Wordy Wordy
224
956 (avg. 4.3)
132 (58.9%)
11 (4.9%)
Bob Bob
496
1,393 (avg. 2.8)
338 (68.1%)
13 (2.6%)
Complex Numbers Complex Numbers
301
742 (avg. 2.5)
219 (72.8%)
3 (1.0%)
Sum of Multiples Sum of Multiples
477
991 (avg. 2.1)
303 (63.5%)
9 (1.9%)
Two Bucket Two Bucket
128
399 (avg. 3.1)
68 (53.1%)
0 (0.0%)
Anagram Anagram
472
1,081 (avg. 2.3)
302 (64.0%)
14 (3.0%)
Binary Search Tree Binary Search Tree
349
1,056 (avg. 3.0)
171 (49.0%)
27 (7.7%)
Say Say
174
657 (avg. 3.8)
91 (52.3%)
1 (0.6%)
ETL ETL
236
754 (avg. 3.2)
146 (61.9%)
5 (2.1%)
Series Series
337
834 (avg. 2.5)
201 (59.6%)
3 (0.9%)
Diamond Diamond
225
761 (avg. 3.4)
140 (62.2%)
4 (1.8%)
Minesweeper Minesweeper
231
836 (avg. 3.6)
128 (55.4%)
5 (2.2%)
Run-Length Encoding Run-Length Encoding
209
915 (avg. 4.4)
116 (55.5%)
5 (2.4%)
Atbash Cipher Atbash Cipher
310
1,039 (avg. 3.4)
197 (63.5%)
26 (8.4%)
Crypto Square Crypto Square
179
657 (avg. 3.7)
105 (58.7%)
0 (0.0%)
React React
481
1,967 (avg. 4.1)
105 (21.8%)
14 (2.9%)
Prime Factors Prime Factors
254
637 (avg. 2.5)
153 (60.2%)
3 (1.2%)
Nth Prime Nth Prime
328
798 (avg. 2.4)
202 (61.6%)
5 (1.5%)
Perfect Numbers Perfect Numbers
269
812 (avg. 3.0)
187 (69.5%)
2 (0.7%)
Triangle Triangle
382
1,435 (avg. 3.8)
234 (61.3%)
6 (1.6%)
Collatz Conjecture Collatz Conjecture
332
988 (avg. 3.0)
249 (75.0%)
24 (7.2%)
Luhn Luhn
271
1,676 (avg. 6.2)
171 (63.1%)
13 (4.8%)
Palindrome Products Palindrome Products
233
807 (avg. 3.5)
114 (48.9%)
11 (4.7%)
All Your Base All Your Base
288
838 (avg. 2.9)
152 (52.8%)
5 (1.7%)
Scrabble Score Scrabble Score
243
768 (avg. 3.2)
169 (69.5%)
15 (6.2%)
Sublist Sublist
226
793 (avg. 3.5)
122 (54.0%)
7 (3.1%)
Largest Series Product Largest Series Product
243
782 (avg. 3.2)
159 (65.4%)
2 (0.8%)
59 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
High Scores High Scores
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
Reverse String Reverse String
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