6 ms·

Question: "How many computable numbers could a computer compute if a computer could compute all computable numbers?" Woodchucks are curious about this.

• jazzyjackson 5y ago
  I wanted to incorporate this question with an Arduino lesson plan based around key breaking, basically demonstrating that 10,000 combinations might seem like a lot when you're doing it by hand, but a computer can brute force it in no time, so how big does a number have to be before it starts taking serious time for a computer to count to it? That's when I learned compilers will look at your for loops and just predict the result of incrementing a number a million times and skip to the end condition. Was quite a shock to find out the program I write is not the program that runs. I think I added something simple to the loop, like flipping a bit on a digital output to force the loop to actually run.
  • tsimionescu 5y ago
    The best way to achieve this without changing the code would be to modify the variable to be `volatile`. That way you tell the compiler that you actually care about it reading/writing it from/to memory every time it is read/written.
  • kamray23 5y ago
    -O0 turns off optimizations on most reasonable C compilers.
  • lordnacho 5y ago
    Stick random() in there somewhere for each iteration, print it out? Then the optimizer won't be able to just jump to the end.
    • jazzyjackson 5y ago
      Actually yes I think that was what we went with, instead of counting from 0 to MAX_INTEGER we generated random numbers that many times, brute forced integer "keys" just fine.
• sumtechguy 5y ago
  You owe the oracle 32GB of RAM. His game rig is low on memory and hungry.
• tshaddox 5y ago
  Countably many!