• Faresh@lemmy.ml
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        6 months ago

        Why are you casting to void*? How is the compiler supposed to know the size of the data you are dereferencing?

        • xmunk@sh.itjust.works
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          6 months ago

          This would probably cause a compiler error…

          But assuming it doesn’t the context is p_ch = the bits above… the code declaring p_ch isn’t shown but I’m guessing that the value here is actuality a pointer to a pointer so nothing illegal would be happening.

          Lastly… C++ is really lacking in guarantees so you can assign a char to the first byte of an integer - C++ doesn’t generally care what you do unless you go out of bounds.

          The reason I’m casting to void* is just pure comedy.

    • fluckx@lemmy.world
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      6 months ago
      p = 1
      
      x = ++p
      // x = 2
      // p = 2
      
      p = 1
      x  = p++
      // x = 1
      // p = 2
      

      ++p will increase the value and return the new value

      p++ will increase the value and return the old value

      I think p = p + 1 is the same as p++ and not as ++p. No?

      • Tyoda@lemm.ee
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        6 months ago

        In C an assignment is an expression where the value is the new value of what was being assigned to.

        In a = b = 1, both a and b will be 1.

        a = *(p = p + 1)
        

        is the same as

        p += 1
        a = *p
        

        , so ++p.

        • fluckx@lemmy.world
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          6 months ago

          What I meant was:

          In the screenshot it said x = *(++p) and iirc that is not the same as saying x = *(p++) or x = *(p += 1)

          As in my example using ++p will return the new value after increment and p++ or p+=1 will return the value before the increment happens, and then increment the variable.

          Or at least that is how I remember it working based on other languages.

          I’m not sure what the * does, but I’m assuming it might be a pointer reference? I’ve never really learned how to code in c or c++ specifically. Though in other languages ( like PHP which is based on C ) there is a distinct difference between ++p and (p++ or p+= 1)

          The last two behave the same. Though it has been years since I did a lot of coding. Which is why I asked.

          I’ll install the latest PHP runtime tonight and give it a try xD

        • fluckx@lemmy.world
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          6 months ago

          Yes.

          p++ == p+= 1 == p = p + 1 are all the same if you use it in an assignment.

          ++p is different if you use it in an assignment. If it’s in its own line it won’t make much difference.

          That’s the point I was trying to make.

          • SpaceNoodle@lemmy.world
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            6 months ago

            No.

            ++p returns incremented p.

            p += 1 returns incremented p.

            p = p + 1 returns incremented p.

            p++ returns p before it is incremented.