[gregjor]

In The Art Of Computer Programming, one of the most influential and comprehensive series of books on the subject, Knuth uses a fictional assembly language called MIX in the examples. The reader does "just run the program in their head."

In Software Tools Brian Kernighan and P.J. Plauger describe a pseudo-language called RATFOR (Rational Fortran), and then throughout the book implement RATFOR in itself.

Getting feedback while learning to program has a lot of value, but so does learning to think through code in your head. People old enough to remember when you had to wait a day to run your program and get results back (very slow turnaround) know the value of that skill, we used to call it "desk checking" -- reading through your code and running it in your head and on paper.

[disgruntledphd2]

The newer versions use MMIX which is much closer to ARM assembly.

There's a compiler plugin for gcc, and when I worked through volume 1 I did type the code in and run the exercises.

I found it incredibly useful, but obviously YMMV.

[ergocoder]

Sure it is useful to run code in your head. I didn't say we must not think through code.

But to unable to run actual code at all? Come on. Who learns programming that way?

[gregjor]

I don't think anyone suggested that.

[jmalicki]

I suggested that. You should be able to look at algorithmic code and prove it correct without worrying about running it.

[rramadass]

> But to unable to run actual code at all? Come on. Who learns programming that way?

Edsger Dijkstra was a proponent of that approach i.e. develop program and proof by hand in a language for which there is no compiler/interpreter.

I wrote about it here - https://news.ycombinator.com/item?id=47985605