High-school computer science
High-school computer science in one app.
Lessons, step-by-step algorithm animations, multiple-choice tests and C++ problems with automatic grading for grades 9–12, the baccalaureate and olympiads.
- Test 1Accepted
- Test 2Accepted
- Test 3Accepted
- Test 4Time limit
- Test 5Accepted
Score 80 / 100
- 9–12the whole curriculum
- 50+animated algorithms
- 100%offline
How it works
Learn, see, solve, get graded (CodePrepper)
Lessons
Lessons for grades 9 to 12, by chapter: digits, arrays, sorting, matrices, recursion, backtracking, dynamic programming, graphs, trees and a final exam review.
Visualisations
More than 50 algorithms are animated step by step, on your own data, with the pseudocode line highlighted as it runs.
Problems
Every problem has a statement, examples, hints and an official solution, and the editor explains compiler messages in plain words.
Automatic grading
Your program is compiled and run locally against every test, with a verdict for each: correct, wrong answer, time limit exceeded or runtime error.
Progress
Solved problems, lessons read, quiz results and an activity calendar, all stored only on your computer. No ads, no accounts, no internet needed.
About the project
CodePrepper gathers the whole Romanian high-school computer science curriculum (math-informatics track, C++) into an app that works completely offline. Students read the lesson, watch the algorithm animate on their own data, then solve problems and get a score for every test.
It's free for anyone learning, including teachers in the classroom.
A judge on your own computer
Problems come with statements, examples, hints and official solutions. Your code is compiled with the g++ already on your machine and graded test by test: accepted, wrong answer, time limit exceeded or runtime error.
See the algorithm think
More than 50 algorithms — sorts, binary search, the sieve, Euclid, backtracking, BFS, DFS, Dijkstra, Prim, Kruskal, Lee and dynamic programming — animate step by step with the pseudocode line highlighted.
Interactive demo
Grader and visualiser
Submit a solution to the automatic grader, then follow a sorting algorithm step by step.
Problem
Sum of digits
Read a natural number n (0 ≤ n ≤ 1012) and print the sum of its digits.
Example: 9081 → 18 · time limit: 1 second
Takes the last digit with n % 10, then drops it with n / 10.
#include <iostream>
using namespace std;
int main()
{
long long n, s = 0;
cin >> n;
while (n > 0)
{
s = s + n % 10;
n = n / 10;
}
cout << s << '\n';
return 0;
}
- #1n = 7queued0/10
- #2n = 0queued0/15
- #3n = 123queued0/15
- #4n = 90817queued0/20
- #5n = 4567890queued0/20
- #6n = 987654321012queued0/20
In-browser demo with simulated data. The real app does much more.
Features
Lessons for every chapter
By grade and chapter: digits, arrays, sorting, matrices, recursion, backtracking, dynamic programming, graphs, trees and exam revision.
Interactive visualisations
50+ algorithms animated step by step, with highlighted pseudocode and your own input.
Auto-graded problems
Statement, examples, hints and solution. You get a verdict for every test.
Built-in C++ editor
Syntax highlighting, auto-indent and compiler messages explained in plain words.
Multiple-choice tests
Baccalaureate-style quizzes by chapter or mixed, plus a timed simulation.
Progress
Solved problems, lessons read, quiz results and an activity calendar.
Privacy
- Works completely offline: it sends data nowhere.
- No ads, no accounts, no telemetry.
- Programs compile and run locally, with time and output limits.
Questions about CodePrepper
Do I need a C++ compiler?
Only for running and grading programs. CodePrepper finds g++ or clang++ automatically (Code::Blocks, Dev-C++, MSYS2 or WinLibs on Windows). Lessons, visualisations and quizzes work without one.
Is it only in Romanian?
The curriculum content follows the Romanian high-school programme and is written in Romanian.
Can teachers use it in class?
Yes, it's free to use for learning, including in the classroom.
MocaLLM
Elementary Algorithms in C++Contact
Got a project in mind?
Let's talk.
Tell me briefly what you want to build. I'll reply with a concrete proposal: what goes into the first version, how long it takes and what the steps look like.