CJCoding With Joseph
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Pick a language to practice

Coding challenges, code walkthroughs, and multiple-choice quizzes in Java, C, C++, JavaScript, C# and SQL.

J

Java

Classes, loops, arrays, methods — the JVM essentials.

456 practice questions
C

C

Pointers, printf, control flow — the systems classic.

480 practice questions
++

C++

Inheritance, classes, streams, and modern C++ basics.

739 practice questions
JS

JavaScript

DOM, loops, console.log — front-end fundamentals.

256 practice questions
C#

C#

OOP done right — classes, properties, interfaces, inheritance, and polymorphism.

790 practice questions
SQL

SQL

Query, join, group and shape data in a real database — levels 1 to 3.

116 practice questions

Or build something from scratch

Spin up a multi-file project in a browser IDE — console apps (C, C++, Java, Python, JavaScript, C#) or web projects (HTML/CSS/JS, React, C# Web UI) with a live preview. Write code, run it, search across files, and keep version history. The IDE also runs Python, which the practice questions above do not cover.

Projects (IDE)

Create your own files and folders and run real programs.

In-browser IDE

Classrooms

Follow full lesson rooms from the Coding With Joseph classroom library.

Lesson library

Daily challenge

One question per language, every day, picked from what you have been practising.

New every day