C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Re: How to design such class?          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message Victor Bazarov Guest Posted: Sat Feb 28, 2004 11:57 pm    Post subject: Re: How to design such class? "alex" <alex (AT) xxx (DOT) net> wrote... Quote: How to design a class that will read raw data from a piece of hardware and the raw data will be constructed as 12-bit images, each 658x342 pixels? When designing a class, do not concern yourself with what it does, but with who and how is going to use the class. The usage will define the class' interface, whereas the needed functionality is just the innards of one or two specific member functions. Victor Back to top Alf P. Steinbach Guest Posted: Sun Feb 29, 2004 12:11 am    Post subject: Re: How to design such class? * "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schriebt: Quote: "alex" <alex (AT) xxx (DOT) net> wrote... How to design a class that will read raw data from a piece of hardware and the raw data will be constructed as 12-bit images, each 658x342 pixels? When designing a class, do not concern yourself with what it does, but with who and how is going to use the class. The usage will define the class' interface, whereas the needed functionality is just the innards of one or two specific member functions. Amen. Just to clarify: alex, your problem isn't best solved by "a class", so forget about "a class". Back to top Razvan Popovici Guest Posted: Sun Feb 29, 2004 8:28 am    Post subject: Re: How to design such class? What about: class CImageClass { public: readDataFromHardware(void*wiredparameter,int intparameter ......); writeDataToFile(const char* filename, .....); private: char[maxData] crawData; bool bisDataInitialised; // false= no data is readed in rawdata, true= data is loaded in rawdata }; According your needs you can allocate rawData dynamically, in constructor and keep the pointer null while no data is readed, so you kick out the isDataInitialised member. Good luck, Razvan Popovici "Alf P. Steinbach" <alfps (AT) start (DOT) no> schrieb im Newsbeitrag news:40412d25.70261937 (AT) news (DOT) individual.net... Quote: * "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schriebt: "alex" <alex (AT) xxx (DOT) net> wrote... How to design a class that will read raw data from a piece of hardware and the raw data will be constructed as 12-bit images, each 658x342 pixels? When designing a class, do not concern yourself with what it does, but with who and how is going to use the class. The usage will define the class' interface, whereas the needed functionality is just the innards of one or two specific member functions. Amen. Just to clarify: alex, your problem isn't best solved by "a class", so forget about "a class". Back to top Victor Bazarov Guest Posted: Sun Feb 29, 2004 2:45 pm    Post subject: Re: How to design such class? "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... Quote: What about: class CImageClass { public: readDataFromHardware(void*wiredparameter,int intparameter ......); writeDataToFile(const char* filename, .....); private: char[maxData] crawData; That's not C++. Quote: bool bisDataInitialised; // false= no data is readed in rawdata, true= data is loaded in rawdata }; According your needs you can allocate rawData dynamically, in constructor Without knowing how much to allocate? Quote: and keep the pointer null while no data is readed, so you kick out the isDataInitialised member. Good luck, Razvan Popovici "Alf P. Steinbach" <alfps (AT) start (DOT) no> schrieb im Newsbeitrag news:40412d25.70261937 (AT) news (DOT) individual.net... * "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schriebt: "alex" <alex (AT) xxx (DOT) net> wrote... How to design a class that will read raw data from a piece of hardware and the raw data will be constructed as 12-bit images, each 658x342 pixels? When designing a class, do not concern yourself with what it does, but with who and how is going to use the class. The usage will define the class' interface, whereas the needed functionality is just the innards of one or two specific member functions. Amen. Just to clarify: alex, your problem isn't best solved by "a class", so forget about "a class". Back to top Razvan Popovici Guest Posted: Sun Feb 29, 2004 9:44 pm    Post subject: Re: How to design such class? "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schrieb im Newsbeitrag news:QVm0c.439540$na.1052068 (AT) attbi_s04 (DOT) .. Quote: "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... What about: class CImageClass { public: readDataFromHardware(void*wiredparameter,int intparameter ......); writeDataToFile(const char* filename, .....); private: char[maxData] crawData; That's not C++. he needs to read data from a _hardware_ device. Just use an autogrow stl array (C++ like) and you will see a real performance reduction. maxData, or better MAXDATA, should be a define symbol or a constant. Quote: bool bisDataInitialised; // false= no data is readed in rawdata, true= data is loaded in rawdata }; According your needs you can allocate rawData dynamically, in constructor Without knowing how much to allocate? We know how much to allocate .. we get the parameters of the image/hardware, etc. If not, we can leave the pointer null and allocate exactly when we are reading data. Quote: and keep the pointer null while no data is readed, so you kick out the isDataInitialised member. Good luck, Razvan Popovici "Alf P. Steinbach" <alfps (AT) start (DOT) no> schrieb im Newsbeitrag news:40412d25.70261937 (AT) news (DOT) individual.net... * "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schriebt: "alex" <alex (AT) xxx (DOT) net> wrote... How to design a class that will read raw data from a piece of hardware and the raw data will be constructed as 12-bit images, each 658x342 pixels? When designing a class, do not concern yourself with what it does, but with who and how is going to use the class. The usage will define the class' interface, whereas the needed functionality is just the innards of one or two specific member functions. Amen. Just to clarify: alex, your problem isn't best solved by "a class", so forget about "a class". Back to top Victor Bazarov Guest Posted: Sun Feb 29, 2004 9:57 pm    Post subject: Re: How to design such class? "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... Quote: "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schrieb im Newsbeitrag news:QVm0c.439540$na.1052068 (AT) attbi_s04 (DOT) .. "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... What about: class CImageClass { public: readDataFromHardware(void*wiredparameter,int intparameter ......); writeDataToFile(const char* filename, .....); private: char[maxData] crawData; That's not C++. he needs to read data from a _hardware_ device. Just use an autogrow stl array (C++ like) and you will see a real performance reduction. maxData, or better MAXDATA, should be a define symbol or a constant. No matter what 'maxData' evaluates to, the declaration char[maxData] crawData; is a simple _syntax_error_. As a first step to understanding others try to interpret their statements without any hidden meaning. Also five or six periods in a row is a syntax error as well. And any function declaration should have the return value type. V Back to top Razvan Popovici Guest Posted: Mon Mar 01, 2004 6:46 pm    Post subject: Re: How to design such class? I was just trying to draft the class implementation, it's obvious that x periods in a row will not compile, but will make the autor of the question understand how the class needs to be developed. About the variable declaration you are right, but again, my concerns were about analisys not programming. Razvan "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schrieb im Newsbeitrag news:3ft0c.10610$PR3.225969 (AT) attbi_s03 (DOT) .. Quote: "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... "Victor Bazarov" <v.Abazarov (AT) comAcast (DOT) net> schrieb im Newsbeitrag news:QVm0c.439540$na.1052068 (AT) attbi_s04 (DOT) .. "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... What about: class CImageClass { public: readDataFromHardware(void*wiredparameter,int intparameter ......); writeDataToFile(const char* filename, .....); private: char[maxData] crawData; That's not C++. he needs to read data from a _hardware_ device. Just use an autogrow stl array (C++ like) and you will see a real performance reduction. maxData, or better MAXDATA, should be a define symbol or a constant. No matter what 'maxData' evaluates to, the declaration char[maxData] crawData; is a simple _syntax_error_. As a first step to understanding others try to interpret their statements without any hidden meaning. Also five or six periods in a row is a syntax error as well. And any function declaration should have the return value type. V Back to top Victor Bazarov Guest Posted: Tue Mar 02, 2004 3:40 am    Post subject: Re: How to design such class? "Razvan Popovici" <me (AT) razvan_nospam (DOT) de> wrote... Quote: I was just trying to draft the class implementation, it's obvious that x periods in a row will not compile, but will make the autor of the question understand how the class needs to be developed. About the variable declaration you are right, but again, my concerns were about analisys not programming. Too bad that you decided to do that in a language newsgroup. Perhaps next time you take it where a particular language rules do not apply. Consider using comments instead of ...... and 'void' where return value type is not important. 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