This course has already ended.

Luet oppimateriaalin englanninkielistä versiota. Mainitsit kuitenkin taustakyselyssä osaavasi suomea. Siksi suosittelemme, että käytät suomenkielistä versiota, joka on testatumpi ja hieman laajempi ja muutenkin mukava.

Suomenkielinen materiaali kyllä esittelee englanninkielisetkin termit. Myös suomenkielisessä materiaalissa käytetään ohjelmaprojektien koodissa englanninkielisiä nimiä kurssin alkupään johdantoesimerkkejä lukuunottamatta.

Voit vaihtaa kieltä A+:n valikon yläreunassa olevasta painikkeesta. Tai tästä: Vaihda suomeksi.

Using the Debugger

About This Page:

Questions Answered: How can I execute my program step by step and examine what it does? What’s a good tool for hunting runtime errors?

Prerequisites: This page assumes prior knowledge of topics from Weeks 1 to 4. You can make the most of this page if you read it sometime after reaching Chapter 4.1.

Points Available: None. This material is optional.

Related Projects: Miscellaneous.

Page unavailable in English at the moment   :-(

Due to time pressures, this page hasn’t been translated yet for the first English-language offering of O1 in Fall 2018.

We are sorry.

Fortunately, the chapter is optional and there are other resources available in English that cover the same material.

We’ll try and get an English translation up as soon as possible. In the meantime, you can read up on debuggers in general on Wikipedia. and the debugger in Eclipse’s Scala IDE on that project’s web site

Summary of Key Points

  • A programmer often needs to mentally run programs step by step.
  • There is software that can help the programmer reason about programs. These tools are especially useful when the program is unfamiliar, buggy, and/or complex.
  • A debugger is an auxiliary program that lets the programmer examine the intermediate stages of a program run and the state of the program at those stages.
  • Eclipse’s Scala IDE has a debugger built in. You may find it useful in O1 and elsewhere.
  • Links to the glossary: debugger, breakpoint.



Thousands of students have given feedback that has contributed to this ebook’s design. Thank you!

Weeks 1 to 13 of the ebook, including the assignments and weekly bulletins, have been written in Finnish and translated into English by Juha Sorva.

Weeks 14 to 20 are by Otto Seppälä. That part of the ebook isn’t available during the fall term, but we’ll publish it when it’s time.

The appendices (glossary, Scala reference, FAQ, etc.) are by Juha Sorva unless otherwise specified on the page.

The automatic assessment of the assignments has been programmed by Riku Autio, Jaakko Kantojärvi, Teemu Lehtinen, Timi Seppälä, Teemu Sirkiä, and Aleksi Vartiainen.

The illustrations at the top of each chapter, and the similar drawings elsewhere in the ebook, are the work of Christina Lassheikki.

The animations that detail the execution Scala programs have been designed by Juha Sorva and Teemu Sirkiä. Teemu Sirkiä and Riku Autio have done the technical implementation, relying on Teemu’s Jsvee and Kelmu toolkits.

The other diagrams and interactive presentations in the ebook are by Juha Sorva.

The O1Library software has been developed by Aleksi Lukkarinen and Juha Sorva. Several of its key components are built upon Aleksi’s SMCL library.

The pedagogy of using tools from O1Library (such as Pic) for simple graphical programming is inspired by the textbooks How to Design Programs by Flatt, Felleisen, Findler, and Krishnamurthi and Picturing Programs by Stephen Bloch.

The course platform A+ has been created by Aalto’s LeTech research group and is largely developed by students. The current lead developer is Jaakko Kantojärvi; many other students of computer science and information networks are also active on the project.

For O1’s current teaching staff, please see Chapter 1.1.

Additional credits appear at the ends of some chapters.

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