Compare a given version number in the form major.minor.build.patch and see if one is less than the other Announcing the arrival of Valued Associate #679: Cesar Manara Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Displaying the number of elements larger than the average of an arrayFirst prime number larger than given integerFind smallest prime number greater than given nPrinting twin primes less than a given natural number nFind how many numbers in an array are less than each number in the arraySimple pool of threads which calculate the sum of a given number from the main processCalculate the number of palindrome numbers in the given rangesA program to find out the number of odd and even Fibonacci numbers between given rangeFind the smallest number in the first array that is not in the second oneFind the sum of the digits of a given number

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Compare a given version number in the form major.minor.build.patch and see if one is less than the other



Announcing the arrival of Valued Associate #679: Cesar Manara
Planned maintenance scheduled April 17/18, 2019 at 00:00UTC (8:00pm US/Eastern)Displaying the number of elements larger than the average of an arrayFirst prime number larger than given integerFind smallest prime number greater than given nPrinting twin primes less than a given natural number nFind how many numbers in an array are less than each number in the arraySimple pool of threads which calculate the sum of a given number from the main processCalculate the number of palindrome numbers in the given rangesA program to find out the number of odd and even Fibonacci numbers between given rangeFind the smallest number in the first array that is not in the second oneFind the sum of the digits of a given number



.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;








4












$begingroup$


#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

typedef int STATUS;
#define ERROR -1
#define OKAY 0

struct version

unsigned char major;
unsigned char minor;
unsigned char build;
unsigned char patch;
;
STATUS is_less_than(struct version * original, struct version *compared, bool *result)
compared == NULL


Is there a cleaner way to do this?










share|improve this question









$endgroup$


















    4












    $begingroup$


    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <stdbool.h>

    typedef int STATUS;
    #define ERROR -1
    #define OKAY 0

    struct version

    unsigned char major;
    unsigned char minor;
    unsigned char build;
    unsigned char patch;
    ;
    STATUS is_less_than(struct version * original, struct version *compared, bool *result)
    compared == NULL


    Is there a cleaner way to do this?










    share|improve this question









    $endgroup$














      4












      4








      4





      $begingroup$


      #include <stdio.h>
      #include <stdlib.h>
      #include <string.h>
      #include <stdbool.h>

      typedef int STATUS;
      #define ERROR -1
      #define OKAY 0

      struct version

      unsigned char major;
      unsigned char minor;
      unsigned char build;
      unsigned char patch;
      ;
      STATUS is_less_than(struct version * original, struct version *compared, bool *result)
      compared == NULL


      Is there a cleaner way to do this?










      share|improve this question









      $endgroup$




      #include <stdio.h>
      #include <stdlib.h>
      #include <string.h>
      #include <stdbool.h>

      typedef int STATUS;
      #define ERROR -1
      #define OKAY 0

      struct version

      unsigned char major;
      unsigned char minor;
      unsigned char build;
      unsigned char patch;
      ;
      STATUS is_less_than(struct version * original, struct version *compared, bool *result)
      compared == NULL


      Is there a cleaner way to do this?







      c






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 6 hours ago









      the_endianthe_endian

      406312




      406312




















          3 Answers
          3






          active

          oldest

          votes


















          5












          $begingroup$

          Yes, there is a cleaner way:



          if (a.major != b.major) 
          *result = a.major < b.major;
          else if (a.minor != b.minor)
          *result = a.minor < b.minor;
          else if (a.patch != b.patch)
          *result = a.patch < b.patch;
          else
          *result = a.build < b.build;

          return OKAY;


          I reordered patch to come before build since that's how it is usually done. If your version scheme is different from this, good luck.



          Instead of unsigned char I would choose unsigned int so that your code can handle versions like 1.0.20190415.






          share|improve this answer











          $endgroup$












          • $begingroup$
            Nice catch on the patch, build ordering.
            $endgroup$
            – Costantino Grana
            2 hours ago


















          2












          $begingroup$

          I don't see any advantage to having the function to take three pointers (two for input and one for output) and return a status code. As a result of that unnecessarily error-prone design, the function has to handle the possibility of null pointers, and the caller is expected to handle a status code. But why should such a simple comparison have these failure modes at all?



          The danger is further complicated by the fact that neither of the in-parameters is declared const.



          Just pass the two versions by value, and you would eliminate all of that complication! On any modern 32-bit or 64-bit processor, passing a four-byte struct by value should actually be more efficient than passing it by reference — especially since you don't have to dereference the pointers to access each field.



          With all of the potential errors out of the way, taking @RolandIllig's suggestion, you could then reduce it down to one chained conditional expression:



          bool is_less_than(struct version a, struct version b) 
          return a.major != b.major ? a.major < b.major :
          a.minor != b.minor ? a.minor < b.minor :
          a.patch != b.patch ? a.patch < b.patch :
          a.build < b.build;



          I'd go further and recommend using unsigned short instead of unsigned char for the fields. Using unsigned char for numeric values is awkward, since you would have to cast them when using printf(). On a 64-bit architecture, a struct with four 2-byte fields would occupy 64 bits, so you wouldn't be saving anything by using unsigned char instead of unsigned short.






          share|improve this answer









          $endgroup$




















            0












            $begingroup$

            Return status



            You create this:



            typedef int STATUS;
            #define ERROR -1
            #define OKAY 0


            which is basically a boolean status. Personally, I'd return a straight bool.



            Bug/Not what you mean



            Doing a



            result = NULL;


            is changing the local variable (parameter) result. It's not setting the result to NULL. In fact the caller won't probably have a pointer at all, but just a bool, which cannot properly be NULL.



            Shorter version



            I'm not sure this is cleaner, but here I go:



            bool is_less_than(struct version * original, struct version *compared, bool *result)



            Next time, add a driver/test suite to your question, to ease the life of people answering. This can be one:



            int main(void) 

            struct version ref = 1, 2, 21, 8 ;
            struct version lower1 = 0, 2, 21, 8 ;
            struct version lower2 = 1, 1, 21, 8 ;
            struct version lower3 = 1, 2, 20, 8 ;
            struct version lower4 = 1, 2, 21, 7 ;
            struct version equal = 1, 2, 21, 8 ;
            struct version higher1 = 2, 2, 21, 8 ;
            struct version higher2 = 1, 3, 21, 8 ;
            struct version higher3 = 1, 2, 22, 8 ;
            struct version higher4 = 1, 2, 21, 9 ;

            #define TEST(a,b,expect1,expect2)
            do
            bool result1, result2;
            is_less_than((a), (b), &result1);
            is_less_than((b), (a), &result2);
            puts(result1==(expect1) && result2==(expect2)?"ok":"failed");
            while(0)
            #define TESTL(a,b) TEST(a,b,true,false)
            #define TESTE(a,b) TEST(a,b,false,false)
            #define TESTH(a,b) TEST(a,b,false,true)

            TESTL(&lower1, &ref);
            TESTL(&lower2, &ref);
            TESTL(&lower3, &ref);
            TESTL(&lower4, &ref);
            TESTE(&equal, &ref);
            TESTH(&higher1, &ref);
            TESTH(&higher2, &ref);
            TESTH(&higher3, &ref);
            TESTH(&higher4, &ref);

            return 0;






            share|improve this answer











            $endgroup$








            • 1




              $begingroup$
              As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
              $endgroup$
              – Roland Illig
              2 hours ago











            • $begingroup$
              @RolandIllig Updated. Thank you for the suggestion.
              $endgroup$
              – Costantino Grana
              2 hours ago











            Your Answer






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            3 Answers
            3






            active

            oldest

            votes








            3 Answers
            3






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            5












            $begingroup$

            Yes, there is a cleaner way:



            if (a.major != b.major) 
            *result = a.major < b.major;
            else if (a.minor != b.minor)
            *result = a.minor < b.minor;
            else if (a.patch != b.patch)
            *result = a.patch < b.patch;
            else
            *result = a.build < b.build;

            return OKAY;


            I reordered patch to come before build since that's how it is usually done. If your version scheme is different from this, good luck.



            Instead of unsigned char I would choose unsigned int so that your code can handle versions like 1.0.20190415.






            share|improve this answer











            $endgroup$












            • $begingroup$
              Nice catch on the patch, build ordering.
              $endgroup$
              – Costantino Grana
              2 hours ago















            5












            $begingroup$

            Yes, there is a cleaner way:



            if (a.major != b.major) 
            *result = a.major < b.major;
            else if (a.minor != b.minor)
            *result = a.minor < b.minor;
            else if (a.patch != b.patch)
            *result = a.patch < b.patch;
            else
            *result = a.build < b.build;

            return OKAY;


            I reordered patch to come before build since that's how it is usually done. If your version scheme is different from this, good luck.



            Instead of unsigned char I would choose unsigned int so that your code can handle versions like 1.0.20190415.






            share|improve this answer











            $endgroup$












            • $begingroup$
              Nice catch on the patch, build ordering.
              $endgroup$
              – Costantino Grana
              2 hours ago













            5












            5








            5





            $begingroup$

            Yes, there is a cleaner way:



            if (a.major != b.major) 
            *result = a.major < b.major;
            else if (a.minor != b.minor)
            *result = a.minor < b.minor;
            else if (a.patch != b.patch)
            *result = a.patch < b.patch;
            else
            *result = a.build < b.build;

            return OKAY;


            I reordered patch to come before build since that's how it is usually done. If your version scheme is different from this, good luck.



            Instead of unsigned char I would choose unsigned int so that your code can handle versions like 1.0.20190415.






            share|improve this answer











            $endgroup$



            Yes, there is a cleaner way:



            if (a.major != b.major) 
            *result = a.major < b.major;
            else if (a.minor != b.minor)
            *result = a.minor < b.minor;
            else if (a.patch != b.patch)
            *result = a.patch < b.patch;
            else
            *result = a.build < b.build;

            return OKAY;


            I reordered patch to come before build since that's how it is usually done. If your version scheme is different from this, good luck.



            Instead of unsigned char I would choose unsigned int so that your code can handle versions like 1.0.20190415.







            share|improve this answer














            share|improve this answer



            share|improve this answer








            edited 2 hours ago

























            answered 2 hours ago









            Roland IlligRoland Illig

            11.6k11946




            11.6k11946











            • $begingroup$
              Nice catch on the patch, build ordering.
              $endgroup$
              – Costantino Grana
              2 hours ago
















            • $begingroup$
              Nice catch on the patch, build ordering.
              $endgroup$
              – Costantino Grana
              2 hours ago















            $begingroup$
            Nice catch on the patch, build ordering.
            $endgroup$
            – Costantino Grana
            2 hours ago




            $begingroup$
            Nice catch on the patch, build ordering.
            $endgroup$
            – Costantino Grana
            2 hours ago













            2












            $begingroup$

            I don't see any advantage to having the function to take three pointers (two for input and one for output) and return a status code. As a result of that unnecessarily error-prone design, the function has to handle the possibility of null pointers, and the caller is expected to handle a status code. But why should such a simple comparison have these failure modes at all?



            The danger is further complicated by the fact that neither of the in-parameters is declared const.



            Just pass the two versions by value, and you would eliminate all of that complication! On any modern 32-bit or 64-bit processor, passing a four-byte struct by value should actually be more efficient than passing it by reference — especially since you don't have to dereference the pointers to access each field.



            With all of the potential errors out of the way, taking @RolandIllig's suggestion, you could then reduce it down to one chained conditional expression:



            bool is_less_than(struct version a, struct version b) 
            return a.major != b.major ? a.major < b.major :
            a.minor != b.minor ? a.minor < b.minor :
            a.patch != b.patch ? a.patch < b.patch :
            a.build < b.build;



            I'd go further and recommend using unsigned short instead of unsigned char for the fields. Using unsigned char for numeric values is awkward, since you would have to cast them when using printf(). On a 64-bit architecture, a struct with four 2-byte fields would occupy 64 bits, so you wouldn't be saving anything by using unsigned char instead of unsigned short.






            share|improve this answer









            $endgroup$

















              2












              $begingroup$

              I don't see any advantage to having the function to take three pointers (two for input and one for output) and return a status code. As a result of that unnecessarily error-prone design, the function has to handle the possibility of null pointers, and the caller is expected to handle a status code. But why should such a simple comparison have these failure modes at all?



              The danger is further complicated by the fact that neither of the in-parameters is declared const.



              Just pass the two versions by value, and you would eliminate all of that complication! On any modern 32-bit or 64-bit processor, passing a four-byte struct by value should actually be more efficient than passing it by reference — especially since you don't have to dereference the pointers to access each field.



              With all of the potential errors out of the way, taking @RolandIllig's suggestion, you could then reduce it down to one chained conditional expression:



              bool is_less_than(struct version a, struct version b) 
              return a.major != b.major ? a.major < b.major :
              a.minor != b.minor ? a.minor < b.minor :
              a.patch != b.patch ? a.patch < b.patch :
              a.build < b.build;



              I'd go further and recommend using unsigned short instead of unsigned char for the fields. Using unsigned char for numeric values is awkward, since you would have to cast them when using printf(). On a 64-bit architecture, a struct with four 2-byte fields would occupy 64 bits, so you wouldn't be saving anything by using unsigned char instead of unsigned short.






              share|improve this answer









              $endgroup$















                2












                2








                2





                $begingroup$

                I don't see any advantage to having the function to take three pointers (two for input and one for output) and return a status code. As a result of that unnecessarily error-prone design, the function has to handle the possibility of null pointers, and the caller is expected to handle a status code. But why should such a simple comparison have these failure modes at all?



                The danger is further complicated by the fact that neither of the in-parameters is declared const.



                Just pass the two versions by value, and you would eliminate all of that complication! On any modern 32-bit or 64-bit processor, passing a four-byte struct by value should actually be more efficient than passing it by reference — especially since you don't have to dereference the pointers to access each field.



                With all of the potential errors out of the way, taking @RolandIllig's suggestion, you could then reduce it down to one chained conditional expression:



                bool is_less_than(struct version a, struct version b) 
                return a.major != b.major ? a.major < b.major :
                a.minor != b.minor ? a.minor < b.minor :
                a.patch != b.patch ? a.patch < b.patch :
                a.build < b.build;



                I'd go further and recommend using unsigned short instead of unsigned char for the fields. Using unsigned char for numeric values is awkward, since you would have to cast them when using printf(). On a 64-bit architecture, a struct with four 2-byte fields would occupy 64 bits, so you wouldn't be saving anything by using unsigned char instead of unsigned short.






                share|improve this answer









                $endgroup$



                I don't see any advantage to having the function to take three pointers (two for input and one for output) and return a status code. As a result of that unnecessarily error-prone design, the function has to handle the possibility of null pointers, and the caller is expected to handle a status code. But why should such a simple comparison have these failure modes at all?



                The danger is further complicated by the fact that neither of the in-parameters is declared const.



                Just pass the two versions by value, and you would eliminate all of that complication! On any modern 32-bit or 64-bit processor, passing a four-byte struct by value should actually be more efficient than passing it by reference — especially since you don't have to dereference the pointers to access each field.



                With all of the potential errors out of the way, taking @RolandIllig's suggestion, you could then reduce it down to one chained conditional expression:



                bool is_less_than(struct version a, struct version b) 
                return a.major != b.major ? a.major < b.major :
                a.minor != b.minor ? a.minor < b.minor :
                a.patch != b.patch ? a.patch < b.patch :
                a.build < b.build;



                I'd go further and recommend using unsigned short instead of unsigned char for the fields. Using unsigned char for numeric values is awkward, since you would have to cast them when using printf(). On a 64-bit architecture, a struct with four 2-byte fields would occupy 64 bits, so you wouldn't be saving anything by using unsigned char instead of unsigned short.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered 1 hour ago









                200_success200_success

                131k17157422




                131k17157422





















                    0












                    $begingroup$

                    Return status



                    You create this:



                    typedef int STATUS;
                    #define ERROR -1
                    #define OKAY 0


                    which is basically a boolean status. Personally, I'd return a straight bool.



                    Bug/Not what you mean



                    Doing a



                    result = NULL;


                    is changing the local variable (parameter) result. It's not setting the result to NULL. In fact the caller won't probably have a pointer at all, but just a bool, which cannot properly be NULL.



                    Shorter version



                    I'm not sure this is cleaner, but here I go:



                    bool is_less_than(struct version * original, struct version *compared, bool *result)



                    Next time, add a driver/test suite to your question, to ease the life of people answering. This can be one:



                    int main(void) 

                    struct version ref = 1, 2, 21, 8 ;
                    struct version lower1 = 0, 2, 21, 8 ;
                    struct version lower2 = 1, 1, 21, 8 ;
                    struct version lower3 = 1, 2, 20, 8 ;
                    struct version lower4 = 1, 2, 21, 7 ;
                    struct version equal = 1, 2, 21, 8 ;
                    struct version higher1 = 2, 2, 21, 8 ;
                    struct version higher2 = 1, 3, 21, 8 ;
                    struct version higher3 = 1, 2, 22, 8 ;
                    struct version higher4 = 1, 2, 21, 9 ;

                    #define TEST(a,b,expect1,expect2)
                    do
                    bool result1, result2;
                    is_less_than((a), (b), &result1);
                    is_less_than((b), (a), &result2);
                    puts(result1==(expect1) && result2==(expect2)?"ok":"failed");
                    while(0)
                    #define TESTL(a,b) TEST(a,b,true,false)
                    #define TESTE(a,b) TEST(a,b,false,false)
                    #define TESTH(a,b) TEST(a,b,false,true)

                    TESTL(&lower1, &ref);
                    TESTL(&lower2, &ref);
                    TESTL(&lower3, &ref);
                    TESTL(&lower4, &ref);
                    TESTE(&equal, &ref);
                    TESTH(&higher1, &ref);
                    TESTH(&higher2, &ref);
                    TESTH(&higher3, &ref);
                    TESTH(&higher4, &ref);

                    return 0;






                    share|improve this answer











                    $endgroup$








                    • 1




                      $begingroup$
                      As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
                      $endgroup$
                      – Roland Illig
                      2 hours ago











                    • $begingroup$
                      @RolandIllig Updated. Thank you for the suggestion.
                      $endgroup$
                      – Costantino Grana
                      2 hours ago















                    0












                    $begingroup$

                    Return status



                    You create this:



                    typedef int STATUS;
                    #define ERROR -1
                    #define OKAY 0


                    which is basically a boolean status. Personally, I'd return a straight bool.



                    Bug/Not what you mean



                    Doing a



                    result = NULL;


                    is changing the local variable (parameter) result. It's not setting the result to NULL. In fact the caller won't probably have a pointer at all, but just a bool, which cannot properly be NULL.



                    Shorter version



                    I'm not sure this is cleaner, but here I go:



                    bool is_less_than(struct version * original, struct version *compared, bool *result)



                    Next time, add a driver/test suite to your question, to ease the life of people answering. This can be one:



                    int main(void) 

                    struct version ref = 1, 2, 21, 8 ;
                    struct version lower1 = 0, 2, 21, 8 ;
                    struct version lower2 = 1, 1, 21, 8 ;
                    struct version lower3 = 1, 2, 20, 8 ;
                    struct version lower4 = 1, 2, 21, 7 ;
                    struct version equal = 1, 2, 21, 8 ;
                    struct version higher1 = 2, 2, 21, 8 ;
                    struct version higher2 = 1, 3, 21, 8 ;
                    struct version higher3 = 1, 2, 22, 8 ;
                    struct version higher4 = 1, 2, 21, 9 ;

                    #define TEST(a,b,expect1,expect2)
                    do
                    bool result1, result2;
                    is_less_than((a), (b), &result1);
                    is_less_than((b), (a), &result2);
                    puts(result1==(expect1) && result2==(expect2)?"ok":"failed");
                    while(0)
                    #define TESTL(a,b) TEST(a,b,true,false)
                    #define TESTE(a,b) TEST(a,b,false,false)
                    #define TESTH(a,b) TEST(a,b,false,true)

                    TESTL(&lower1, &ref);
                    TESTL(&lower2, &ref);
                    TESTL(&lower3, &ref);
                    TESTL(&lower4, &ref);
                    TESTE(&equal, &ref);
                    TESTH(&higher1, &ref);
                    TESTH(&higher2, &ref);
                    TESTH(&higher3, &ref);
                    TESTH(&higher4, &ref);

                    return 0;






                    share|improve this answer











                    $endgroup$








                    • 1




                      $begingroup$
                      As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
                      $endgroup$
                      – Roland Illig
                      2 hours ago











                    • $begingroup$
                      @RolandIllig Updated. Thank you for the suggestion.
                      $endgroup$
                      – Costantino Grana
                      2 hours ago













                    0












                    0








                    0





                    $begingroup$

                    Return status



                    You create this:



                    typedef int STATUS;
                    #define ERROR -1
                    #define OKAY 0


                    which is basically a boolean status. Personally, I'd return a straight bool.



                    Bug/Not what you mean



                    Doing a



                    result = NULL;


                    is changing the local variable (parameter) result. It's not setting the result to NULL. In fact the caller won't probably have a pointer at all, but just a bool, which cannot properly be NULL.



                    Shorter version



                    I'm not sure this is cleaner, but here I go:



                    bool is_less_than(struct version * original, struct version *compared, bool *result)



                    Next time, add a driver/test suite to your question, to ease the life of people answering. This can be one:



                    int main(void) 

                    struct version ref = 1, 2, 21, 8 ;
                    struct version lower1 = 0, 2, 21, 8 ;
                    struct version lower2 = 1, 1, 21, 8 ;
                    struct version lower3 = 1, 2, 20, 8 ;
                    struct version lower4 = 1, 2, 21, 7 ;
                    struct version equal = 1, 2, 21, 8 ;
                    struct version higher1 = 2, 2, 21, 8 ;
                    struct version higher2 = 1, 3, 21, 8 ;
                    struct version higher3 = 1, 2, 22, 8 ;
                    struct version higher4 = 1, 2, 21, 9 ;

                    #define TEST(a,b,expect1,expect2)
                    do
                    bool result1, result2;
                    is_less_than((a), (b), &result1);
                    is_less_than((b), (a), &result2);
                    puts(result1==(expect1) && result2==(expect2)?"ok":"failed");
                    while(0)
                    #define TESTL(a,b) TEST(a,b,true,false)
                    #define TESTE(a,b) TEST(a,b,false,false)
                    #define TESTH(a,b) TEST(a,b,false,true)

                    TESTL(&lower1, &ref);
                    TESTL(&lower2, &ref);
                    TESTL(&lower3, &ref);
                    TESTL(&lower4, &ref);
                    TESTE(&equal, &ref);
                    TESTH(&higher1, &ref);
                    TESTH(&higher2, &ref);
                    TESTH(&higher3, &ref);
                    TESTH(&higher4, &ref);

                    return 0;






                    share|improve this answer











                    $endgroup$



                    Return status



                    You create this:



                    typedef int STATUS;
                    #define ERROR -1
                    #define OKAY 0


                    which is basically a boolean status. Personally, I'd return a straight bool.



                    Bug/Not what you mean



                    Doing a



                    result = NULL;


                    is changing the local variable (parameter) result. It's not setting the result to NULL. In fact the caller won't probably have a pointer at all, but just a bool, which cannot properly be NULL.



                    Shorter version



                    I'm not sure this is cleaner, but here I go:



                    bool is_less_than(struct version * original, struct version *compared, bool *result)



                    Next time, add a driver/test suite to your question, to ease the life of people answering. This can be one:



                    int main(void) 

                    struct version ref = 1, 2, 21, 8 ;
                    struct version lower1 = 0, 2, 21, 8 ;
                    struct version lower2 = 1, 1, 21, 8 ;
                    struct version lower3 = 1, 2, 20, 8 ;
                    struct version lower4 = 1, 2, 21, 7 ;
                    struct version equal = 1, 2, 21, 8 ;
                    struct version higher1 = 2, 2, 21, 8 ;
                    struct version higher2 = 1, 3, 21, 8 ;
                    struct version higher3 = 1, 2, 22, 8 ;
                    struct version higher4 = 1, 2, 21, 9 ;

                    #define TEST(a,b,expect1,expect2)
                    do
                    bool result1, result2;
                    is_less_than((a), (b), &result1);
                    is_less_than((b), (a), &result2);
                    puts(result1==(expect1) && result2==(expect2)?"ok":"failed");
                    while(0)
                    #define TESTL(a,b) TEST(a,b,true,false)
                    #define TESTE(a,b) TEST(a,b,false,false)
                    #define TESTH(a,b) TEST(a,b,false,true)

                    TESTL(&lower1, &ref);
                    TESTL(&lower2, &ref);
                    TESTL(&lower3, &ref);
                    TESTL(&lower4, &ref);
                    TESTE(&equal, &ref);
                    TESTH(&higher1, &ref);
                    TESTH(&higher2, &ref);
                    TESTH(&higher3, &ref);
                    TESTH(&higher4, &ref);

                    return 0;







                    share|improve this answer














                    share|improve this answer



                    share|improve this answer








                    edited 2 hours ago

























                    answered 2 hours ago









                    Costantino GranaCostantino Grana

                    18728




                    18728







                    • 1




                      $begingroup$
                      As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
                      $endgroup$
                      – Roland Illig
                      2 hours ago











                    • $begingroup$
                      @RolandIllig Updated. Thank you for the suggestion.
                      $endgroup$
                      – Costantino Grana
                      2 hours ago












                    • 1




                      $begingroup$
                      As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
                      $endgroup$
                      – Roland Illig
                      2 hours ago











                    • $begingroup$
                      @RolandIllig Updated. Thank you for the suggestion.
                      $endgroup$
                      – Costantino Grana
                      2 hours ago







                    1




                    1




                    $begingroup$
                    As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
                    $endgroup$
                    – Roland Illig
                    2 hours ago





                    $begingroup$
                    As for every comparator function, the driver/test should compare each pair of example data to at least ensure that the ordering is transitive and that less(x, x) is never true.
                    $endgroup$
                    – Roland Illig
                    2 hours ago













                    $begingroup$
                    @RolandIllig Updated. Thank you for the suggestion.
                    $endgroup$
                    – Costantino Grana
                    2 hours ago




                    $begingroup$
                    @RolandIllig Updated. Thank you for the suggestion.
                    $endgroup$
                    – Costantino Grana
                    2 hours ago

















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