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  4. Today's entry for the "kill it with fire" list

Today's entry for the "kill it with fire" list

Scheduled Pinned Locked Moved The Weird and The Wonderful
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  • G Gary Wheeler

    bool flags[2];
    //...
    if ( (flags[0] == true) ||
    (flags[1] == true) )
    {
    //...
    if ( (flags[0] == TRUE) ||
    (flags[1] == TRUE) )
    {
    }
    }

    X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

    Software Zen: delete this;

    R Offline
    R Offline
    Ron Anders
    wrote on last edited by
    #5

    :-D

    1 Reply Last reply
    0
    • G Gary Wheeler

      bool flags[2];
      //...
      if ( (flags[0] == true) ||
      (flags[1] == true) )
      {
      //...
      if ( (flags[0] == TRUE) ||
      (flags[1] == TRUE) )
      {
      }
      }

      X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

      Software Zen: delete this;

      B Offline
      B Offline
      Bernhard Hiller
      wrote on last edited by
      #6

      Oh no, that can be not only valid, but also necessary... Can you be sure that there's not some strange #define somewhere changing the meaning of TRUE or true? And when the flags array is a member of the class (instead of locally declared in a function), its values can be changed from where ever in a different thread. Just make sure you cope with such threats. :-D

      Oh sanctissimi Wilhelmus, Theodorus, et Fredericus!

      G 1 Reply Last reply
      0
      • B Bernhard Hiller

        Oh no, that can be not only valid, but also necessary... Can you be sure that there's not some strange #define somewhere changing the meaning of TRUE or true? And when the flags array is a member of the class (instead of locally declared in a function), its values can be changed from where ever in a different thread. Just make sure you cope with such threats. :-D

        Oh sanctissimi Wilhelmus, Theodorus, et Fredericus!

        G Offline
        G Offline
        Gary Wheeler
        wrote on last edited by
        #7

        Bernhard Hiller wrote:

        #define somewhere changing the meaning of TRUE or true?

        Even more reason to break out the flamethrower... :laugh:

        Software Zen: delete this;

        1 Reply Last reply
        0
        • G Gary Wheeler

          Yes, and the flags aren't changed anywhere inside the intervening 'logic'. Not only does he compare a bool to true, he also compares it to the Windows-defined TRUE as well, which is not really the same thing.

          Software Zen: delete this;

          D Offline
          D Offline
          DJ van Wyk
          wrote on last edited by
          #8

          What if, 15 years down the line, someone inserts code between the two different checks that changes the value of TRUE? You have to make absolutely sure that it is still true when the really important piece of code hits. I suggest you add a few inline ifs so that there will never be any doubt.

          My plan is to live forever ... so far so good

          N 1 Reply Last reply
          0
          • G Gary Wheeler

            bool flags[2];
            //...
            if ( (flags[0] == true) ||
            (flags[1] == true) )
            {
            //...
            if ( (flags[0] == TRUE) ||
            (flags[1] == TRUE) )
            {
            }
            }

            X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

            Software Zen: delete this;

            M Offline
            M Offline
            Member 9167057
            wrote on last edited by
            #9

            Hey, I recently removed code toying with the global BoolStr variable because some table-internal-to-the-program had to use yes/no instead of true/false which as easily readable but doesn't require meddling with globals.

            1 Reply Last reply
            0
            • G Gary Wheeler

              bool flags[2];
              //...
              if ( (flags[0] == true) ||
              (flags[1] == true) )
              {
              //...
              if ( (flags[0] == TRUE) ||
              (flags[1] == TRUE) )
              {
              }
              }

              X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

              Software Zen: delete this;

              E Offline
              E Offline
              englebart
              wrote on last edited by
              #10

              just add this code before the first if statement:

              if (flags[0] == TRUE) flags[0] = true;
              if (flags[1] == TRUE) flags[1] = true;
              if (flags[0] == FALSE) flags[0] = false;
              if (flags[1] == FALSE) flags[1] = false;

              Then you can trust !(not), && and || for the rest of the checks. Or better yet, with 2 Booleans, there are only four possible states, so normalize and then turn it into a switch statement with 0-3.

              if (flags\[0\] == TRUE) flags\[0\] = true;
              if (flags\[1\] == TRUE) flags\[1\] = true;
              if (flags\[0\] == FALSE) flags\[0\] = false;
              if (flags\[1\] == FALSE) flags\[1\] = false;
              int state;
              if (flags\[0\]) 
                  state = 1
              else 
                  state = 0;
              if (flags\[1\]) state += 2;
              switch (state) {case 0-3:...}
              
              G 1 Reply Last reply
              0
              • E englebart

                just add this code before the first if statement:

                if (flags[0] == TRUE) flags[0] = true;
                if (flags[1] == TRUE) flags[1] = true;
                if (flags[0] == FALSE) flags[0] = false;
                if (flags[1] == FALSE) flags[1] = false;

                Then you can trust !(not), && and || for the rest of the checks. Or better yet, with 2 Booleans, there are only four possible states, so normalize and then turn it into a switch statement with 0-3.

                if (flags\[0\] == TRUE) flags\[0\] = true;
                if (flags\[1\] == TRUE) flags\[1\] = true;
                if (flags\[0\] == FALSE) flags\[0\] = false;
                if (flags\[1\] == FALSE) flags\[1\] = false;
                int state;
                if (flags\[0\]) 
                    state = 1
                else 
                    state = 0;
                if (flags\[1\]) state += 2;
                switch (state) {case 0-3:...}
                
                G Offline
                G Offline
                Gary Wheeler
                wrote on last edited by
                #11

                My gastrointestinal tract just inverted itself... X|

                Software Zen: delete this;

                E 1 Reply Last reply
                0
                • G Gary Wheeler

                  bool flags[2];
                  //...
                  if ( (flags[0] == true) ||
                  (flags[1] == true) )
                  {
                  //...
                  if ( (flags[0] == TRUE) ||
                  (flags[1] == TRUE) )
                  {
                  }
                  }

                  X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

                  Software Zen: delete this;

                  P Offline
                  P Offline
                  Paulo_JCG
                  wrote on last edited by
                  #12

                  Is it possible we're talking about Quantum bool ????

                  Paulo Gomes Measuring programming progress by lines of code is like measuring aircraft building progress by weight. —Bill Gates Everything should be made as simple as possible, but not simpler. —Albert Einstein

                  G 1 Reply Last reply
                  0
                  • P Paulo_JCG

                    Is it possible we're talking about Quantum bool ????

                    Paulo Gomes Measuring programming progress by lines of code is like measuring aircraft building progress by weight. —Bill Gates Everything should be made as simple as possible, but not simpler. —Albert Einstein

                    G Offline
                    G Offline
                    Gary Wheeler
                    wrote on last edited by
                    #13

                    Only this[^] knows.

                    Software Zen: delete this;

                    1 Reply Last reply
                    0
                    • G Gary Wheeler

                      bool flags[2];
                      //...
                      if ( (flags[0] == true) ||
                      (flags[1] == true) )
                      {
                      //...
                      if ( (flags[0] == TRUE) ||
                      (flags[1] == TRUE) )
                      {
                      }
                      }

                      X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

                      Software Zen: delete this;

                      S Offline
                      S Offline
                      S Mercurio
                      wrote on last edited by
                      #14

                      Maybe it's an existential program looking for the meaning of truth and it couldn't get a hold of Stephen Colbert.

                      1 Reply Last reply
                      0
                      • G Gary Wheeler

                        My gastrointestinal tract just inverted itself... X|

                        Software Zen: delete this;

                        E Offline
                        E Offline
                        englebart
                        wrote on last edited by
                        #15

                        Even worse: If the //... code that initializes the flags array really assigns those values into it, then it looks like the original code does not even consider these cases: x == true && y == TRUE. 2 variables with 4 possible values each means there should be 16 possible states. Normalizing the values reduces it to 2 variables with 2 possible values which gives 4 states. If true vs TRUE produce different outcomes, then God bless you and convert the "bools" into an enum. Consider creating a multidimensional array where the indexes are your "flags" and you initialize each array element to be the correct answer for that combination of states.

                        1 Reply Last reply
                        0
                        • G Gary Wheeler

                          bool flags[2];
                          //...
                          if ( (flags[0] == true) ||
                          (flags[1] == true) )
                          {
                          //...
                          if ( (flags[0] == TRUE) ||
                          (flags[1] == TRUE) )
                          {
                          }
                          }

                          X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

                          Software Zen: delete this;

                          D Offline
                          D Offline
                          DSewhuk
                          wrote on last edited by
                          #16

                          might get corrupted to equal, say 42. Code that didn't explicitly check consistently for "==true" would take the wrong path. if(flags[x]) would be true, if(flags[x]==true) would be false. Then you also get the VB true, which is -1!

                          1 Reply Last reply
                          0
                          • D DJ van Wyk

                            What if, 15 years down the line, someone inserts code between the two different checks that changes the value of TRUE? You have to make absolutely sure that it is still true when the really important piece of code hits. I suggest you add a few inline ifs so that there will never be any doubt.

                            My plan is to live forever ... so far so good

                            N Offline
                            N Offline
                            Nathan Minier
                            wrote on last edited by
                            #17

                            To quote my "favorite comment":

                            #define TRUE FALSE
                            //Happy debugging suckers

                            "Never attribute to malice that which can be explained by stupidity." - Hanlon's Razor

                            1 Reply Last reply
                            0
                            • G Gary Wheeler

                              bool flags[2];
                              //...
                              if ( (flags[0] == true) ||
                              (flags[1] == true) )
                              {
                              //...
                              if ( (flags[0] == TRUE) ||
                              (flags[1] == TRUE) )
                              {
                              }
                              }

                              X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

                              Software Zen: delete this;

                              S Offline
                              S Offline
                              Super Lloyd
                              wrote on last edited by
                              #18

                              what if var TRUE = false; hey!? I betcha didn't think of it, did ya?! :omg: ;P

                              A new .NET Serializer All in one Menu-Ribbon Bar Taking over the world since 1371!

                              G 1 Reply Last reply
                              0
                              • S Super Lloyd

                                what if var TRUE = false; hey!? I betcha didn't think of it, did ya?! :omg: ;P

                                A new .NET Serializer All in one Menu-Ribbon Bar Taking over the world since 1371!

                                G Offline
                                G Offline
                                Gary Wheeler
                                wrote on last edited by
                                #19

                                This is C++, fortunately.

                                Software Zen: delete this;

                                S 1 Reply Last reply
                                0
                                • G Gary Wheeler

                                  This is C++, fortunately.

                                  Software Zen: delete this;

                                  S Offline
                                  S Offline
                                  Super Lloyd
                                  wrote on last edited by
                                  #20

                                  well, you know #undef TRUE #define TRUE 0

                                  A new .NET Serializer All in one Menu-Ribbon Bar Taking over the world since 1371!

                                  1 Reply Last reply
                                  0
                                  • G Gary Wheeler

                                    bool flags[2];
                                    //...
                                    if ( (flags[0] == true) ||
                                    (flags[1] == true) )
                                    {
                                    //...
                                    if ( (flags[0] == TRUE) ||
                                    (flags[1] == TRUE) )
                                    {
                                    }
                                    }

                                    X| I just found this in some code I have to extend to support a new feature. I wonder if Mike Rowe[^] knows C++...

                                    Software Zen: delete this;

                                    T Offline
                                    T Offline
                                    TheGreatAndPowerfulOz
                                    wrote on last edited by
                                    #21

                                    This could make sense in a multithreaded situation, but somehow I've a feeling that's not what you're dealing with...

                                    #SupportHeForShe Government can give you nothing but what it takes from somebody else. A government big enough to give you everything you want is big enough to take everything you've got, including your freedom.-Ezra Taft Benson You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun

                                    G 1 Reply Last reply
                                    0
                                    • T TheGreatAndPowerfulOz

                                      This could make sense in a multithreaded situation, but somehow I've a feeling that's not what you're dealing with...

                                      #SupportHeForShe Government can give you nothing but what it takes from somebody else. A government big enough to give you everything you want is big enough to take everything you've got, including your freedom.-Ezra Taft Benson You must accept 1 of 2 basic premises: Either we are alone in the universe or we are not alone. Either way, the implications are staggering!-Wernher von Braun

                                      G Offline
                                      G Offline
                                      Gary Wheeler
                                      wrote on last edited by
                                      #22

                                      While this code was in fact multithreaded, that had nothing to do with the sloppy way the logic was coded. I've had very few cases where comparing a bool variable to a constant made more sense algorithmically than just using the variable as-is. The second part comparing the variable to the Windows DWORD constant TRUE is just plain stupid. It works, but that's no credit.

                                      Software Zen: delete this;

                                      1 Reply Last reply
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