Challenge Library
Coding Challenges
5,893 curated questions across every arena — browse by topic, then jump into a live 3-minute battle to put them to the test.
Filter by type
Filter by difficulty
Popular topics
5,893 challenges total
- Multiple ChoiceBeginner
C: float type
cbeginner - Multiple ChoiceBeginner
C: double type
cbeginner - Multiple ChoiceBeginner
C: char type
cbeginner - Multiple ChoiceBeginner
C: for loop
cbeginner - Multiple ChoiceBeginner
C: while loop
cbeginner - Multiple ChoiceBeginner
C: do-while
cbeginner - Multiple ChoiceBeginner
C: break
cbeginner - Multiple ChoiceBeginner
C: continue
cbeginner - Multiple ChoiceBeginner
C: switch
cbeginner - Multiple ChoiceBeginner
C: ++ operator
cbeginner - Multiple ChoiceBeginner
C: -- operator
cbeginner - Multiple ChoiceBeginner
C: logical AND
cbeginner - Multiple ChoiceBeginner
C: logical OR
cbeginner - Multiple ChoiceBeginner
C: not operator
cbeginner - Multiple ChoiceBeginner
C: equality
cbeginner - Multiple ChoiceBeginner
C: assignment vs equality
cbeginner - Multiple ChoiceBeginner
C: ternary
cbeginner - Multiple ChoiceBeginner
C: short-circuit
cbeginner - Multiple ChoiceBeginner
C: comma operator
cbeginner - Multiple ChoiceBeginner
C: cast
cbeginner - Multiple ChoiceBeginner
C: implicit cast
cbeginner - Multiple ChoiceBeginner
C: unsigned
cbeginner - Multiple ChoiceBeginner
C: sizeof operator
cbeginner - Multiple ChoiceBeginner
C: static variable
cbeginner - Multiple ChoiceBeginner
C: global variable
cbeginner - Multiple ChoiceBeginner
C: extern (b29)
cbeginner - Multiple ChoiceBeginner
C: register
cbeginner - Multiple ChoiceBeginner
Pointer Arithmetic
cbeginner - Multiple ChoiceBeginner
Void Pointer
cbeginner - Multiple ChoiceBeginner
Array vs Pointer
cbeginner - Multiple ChoiceBeginner
String Literal
cbeginner - Multiple ChoiceBeginner
strlen Function
cbeginner - Multiple ChoiceBeginner
strcpy Function
cbeginner - Multiple ChoiceBeginner
strcmp Function
cbeginner - Multiple ChoiceBeginner
strcat Function
cbeginner - Multiple ChoiceBeginner
sprintf Function
cbeginner - Multiple ChoiceBeginner
Buffer Overflow
cbeginner - Multiple ChoiceBeginner
Stack Memory
cbeginner - Multiple ChoiceBeginner
Heap Memory
cbeginner - Multiple ChoiceBeginner
malloc Return
cbeginner - Multiple ChoiceBeginner
free Function
cbeginner - Multiple ChoiceBeginner
Dangling Pointer
cbeginner - Multiple ChoiceBeginner
Memory Leak
cbeginner - Multiple ChoiceBeginner
calloc vs malloc
cbeginner - Multiple ChoiceBeginner
realloc Function
cbeginner - Multiple ChoiceBeginner
Multi-dim Array
cbeginner - Multiple ChoiceBeginner
2D Array Layout
cbeginner - Multiple ChoiceBeginner
Function Declaration
cbeginner - Multiple ChoiceBeginner
Pass by Value
cbeginner - Multiple ChoiceBeginner
Pass by Pointer
cbeginner - Multiple ChoiceBeginner
Recursion in C
cbeginner - Multiple ChoiceBeginner
Header Files
cbeginner - Multiple ChoiceBeginner
Preprocessor Guard
cbeginner - Multiple ChoiceBeginner
#define Macro
cbeginner - Multiple ChoiceBeginner
gcc Compile
cbeginner - Multiple ChoiceBeginner
Segmentation Fault
cbeginner - Multiple ChoiceBeginner
Undefined Behavior
cbeginner - Multiple ChoiceHard
Flexible Array Member
chard - Multiple ChoiceHard
Designated Initializer
chard - Multiple ChoiceHard
Compound Literal
chard
Practice now, dominate the arena
Every challenge here is drawn from the live Code Royale pool. Review a question, then head to the arena to answer under pressure against a real opponent — 3-minute matches, Elo ranking, and badge tiers on the line.