Fill-in C++

No theory first — memorize the formula. C++ syntax becomes 87 fill-in cards: look, fill along, write from memory. All 12 chapters free; quizzes are one payment.

All the learning is free. Chapter quizzes and daily review are a one-time in-app purchase.

Fill-in C++ turns C++ syntax into formula cards: a fixed skeleton of code with a few labelled blanks. No theory first — memorize the shape, fill in the blanks, and you can write code that runs.

Each card takes three steps, all on one screen: Look — read the skeleton and one filled-in example. Fill along — put the example's values back into the blanks. From memory — get a new task and fill the blanks with no hints. Pass all three and the card joins your review queue.

What's inside · 12 chapters, 41 lessons, 87 formula cards — from what a program looks like to bitwise operators and picking an integer type that fits · 139 exercises: fill in the formula, assemble shuffled lines, predict the output, find the mistake · 12 animations: a variable is a box, how a for loop runs, why array indexes start at 0, the recursion call stack, long long overflow. Pause, step and change speed · Handbook: every formula you have learned, searchable and ready to copy · Mistakes list: anything you get wrong comes back for another try

It will not get you stuck Answers are judged on meaning, not formatting. i++, ++i and i += 1 all count, and so do the different ways to print a newline. Type a full-width semicolon, forget a semicolon or swap the quotes, and it tells you exactly which small slip it was instead of just saying wrong. Whenever you are stuck, the answer and the mnemonic are one tap away.

About the purchase All 12 chapters of formula cards, every animation, every after-lesson exercise, the handbook and the mistakes list stay free forever. No chapter is locked. One payment unlocks all 12 chapter quizzes and unlimited daily review. The first chapter quiz is free to try, and the first three review cards each day are free. Not a subscription. Family Sharing and Restore Purchase are supported.

Offline and private Works entirely offline. No account, no network, nothing collected. iPhone and iPad. English and Simplified Chinese, following your system language.