Printing a line with println
print, println, and escape sequences
Comments and disabled code
Printing the result of an arithmetic expression
Chapter capstone: Aligned output block
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Learn Kotlin through 140+ browser exercises, from printing your first line to working with null safety, collections, and classes.
Someone who has never programmed usually cannot yet predict what a line of code will print or tell why the compiler rejects it. This course teaches Kotlin from that starting point, beginning with a single printed line and adding one construct at a time. 140+ coding exercises run in the browser, where you write the code, run it, and inspect its results, with nothing to install.
You start by printing text and naming values with val and var, then use arithmetic, booleans, strings, if and when, loops, and functions to solve small tasks. Null safety follows: a conversion with toIntOrNull() can fail and readLine() returns a String?, so you learn how ?. and ?: handle a missing value. The middle chapters cover lists, lambdas, collection operations such as filter, map, and groupBy, sets, and maps. Later chapters introduce classes, data classes, objects and enums, inheritance and interfaces, exceptions, extension functions, and simple generics.
Chapter capstones combine what each chapter taught, and three checkpoint quizzes revisit earlier material. The final chapter brings the course together in a text report, an inventory model, and a command loop that processes a list of lines. The course suits anyone with no previous programming experience, and it assumes no knowledge of Java.
