C / C++ / MFC

FirstPrevNext

Re: Pointer to structure problem... Dominik Reichl4-Jun-03 0:48 Dominik Reichl 4-Jun-03 0:48  Sure, this is possible too: struct s_Test { char name[30]; }; s_Test *Test; void main() { Test = new s_Test[10]; memcpy(Test[0].name,"Paul",strlen("Paul")+1); // Do something more delete []Test; Test = NULL; return; } -Dominik _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? Re: Pointer to structure problem... Rage4-Jun-03 0:55 Rage 4-Jun-03 0:55  If you need a table, you need a table. How do you understand a pointer to a structure with instances as well ? To be able to point at something, you need that the something exist in the memory. It is therefor impossible to have a table without allocating some memory for it. ~RaGE(); Thanks guys, have it sorted now. IrishSonic4-Jun-03 2:48 IrishSonic 4-Jun-03 2:48  Thanks, have it sorted and know the reason y it can't just do it like that. thanks for all ur help. grahamoj Re: Pointer to structure problem... John M. Drescher4-Jun-03 4:37 John M. Drescher 4-Jun-03 4:37  What you really need is a vector or list of structures but this is a little too complicated to start off with. You can look up vector or list in the help for examples if you want. I assume that you will not know how many structures you will have at compile time and that is why you want a dynamic array. You can create a large array of pointers to your structure. This will take 4 bytes per element. Then allocate your structures when you need them. Have an integer keep track of the current number of structures. Try this: struct s_Test { char name[30]; } struct s_Test* Test[10]; int nTestCount = 0; void main() { // Add a struct and initialize Test[nTestCount] = new Test; strcpy( Test[nTestCount]->name,"Paul"); nTestCount++; // Add a struct and initialize Test[nTestCount] = new Test; strcpy( Test[nTestCount]->name,"John"); nTestCount++; for(int i=0; i < nTestCount;i++) { printf("%s\n",Test[i]->name); } return; } Does the static variable modifier make variable access faster? Dominik Reichl3-Jun-03 22:48 Dominik Reichl 3-Jun-03 22:48  Hello, Is an access to a variable with static modifier faster than a normal variable? I have a recursive function: void recursiveSolve(char *pszInput, int nItems) { int pArray[10]; // Do some stuff... } The initial contents of pArray doesn't matter, it gets overwritten in all cases. If I declare pArray as static int[], would the recursive function be faster? I don't know, perhaps a static variable has a fixed position in memory and doesn't get allocated again and again when the function calls itself recursively. Do you know? -Dominik _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? Re: Does the static variable modifier make variable access faster? FlyingDancer3-Jun-03 23:19 FlyingDancer 3-Jun-03 23:19  I think so. Because a saying said that the more space, the less time. When stored as static varibles the more space is needed (the none-static varibles will be freed when they won't be needed), so I think the function needs less time to run. Do you think I am right, don't you? LeonOrient Re: Does the static variable modifier make variable access faster? Dominik Reichl3-Jun-03 23:28 Dominik Reichl 3-Jun-03 23:28  I don't know if that saying applies to this problem -Dominik _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? Re: Does the static variable modifier make variable access faster? Andrew Walker4-Jun-03 1:03 Andrew Walker 4-Jun-03 1:03  It shouldn't matter. It would be better to try and optimise using a better algorithm than changing to static variables Using static variables is a C concept rather than a C++ concept. It can be very problematic if you have to port the code into a DLL (look at the MSVC6 STL problems with DLL's for the perfect example) Re: Does the static variable modifier make variable access faster? BhaskarBora4-Jun-03 1:48 BhaskarBora 4-Jun-03 1:48  i am sorry my friend... static variables is not only a concept in C but it is extensibly used in C++ too. infact "static var" concept is not confined to any language or OS. its a generic concept, which is used in many languages and operating systems. there are some solutions, which are best implemented with static concept. "Think big, think fast, think ahead. Ideas are no one's monopoly" Re: Does the static variable modifier make variable access faster? Andrew Walker4-Jun-03 1:53 Andrew Walker 4-Jun-03 1:53  BhaskarBora wrote: static variables is not only a concept in C but it is extensibly used in C++ Perhaps I worded it badly. But being able to do it doesn't mean you should. If you have to do something like this why are there so many discussion about the 'meyers singleton' pattern and order of destruction. Dynamic allocation of memory through a static pointer can be walking a dangerous road. Especially if you need to control the order of destruction. Re: Does the static variable modifier make variable access faster? BhaskarBora4-Jun-03 21:12 BhaskarBora 4-Jun-03 21:12  dear friend ! its up to you how you perceive things ! "Think big, think fast, think ahead. Ideas are no one's monopoly" Re: Does the static variable modifier make variable access faster? BhaskarBora4-Jun-03 1:42 BhaskarBora 4-Jun-03 1:42  hi there .. u r right partly... all static variables (no matter where they are defined) are not created on stack like local vars. and also static vars are created once for a process/program and remain till the end. this is the reason when your function has static var array defined rather than a local var array, the execution is faster. as static var is created during the program startup and in your case not everytime when you invoke the function (recursive or otherwise). if it would have been a local array then execution would have been little slower as compare to the static array version (as OS will allocate the array on stack everytime you call the function and removes it from stack when function returns). static var array is shared in all calls to the function. Also, there is a wastage of memory when you are not using the array. to over come this, you can define a 'int pointer' as static and allocate the memory when you need to use the array. when you no longer want the array, relase the allocated memory. this would be a smart solution ! "Think big, think fast, think ahead. Ideas are no one's monopoly" Re: Does the static variable modifier make variable access faster? Dominik Reichl4-Jun-03 4:42 Dominik Reichl 4-Jun-03 4:42  Thanks! I will try the static pointer idea! -Dominik _outp(0x64, 0xAD); and __asm mov al, 0xAD __asm out 0x64, al do the same... but what do they do?? how to make Floppy-Disk-Device's LED blinking FlyingDancer3-Jun-03 22:25 FlyingDancer 3-Jun-03 22:25  Now I have been assigned a task to do a FDD test. During the project I don't know how to make the Floppy-Disk-Device's LED blinking. Could you tell me some solutions to it, please. Thank you! LeonOrient Re: how to make Floppy-Disk-Device's LED blinking Toni784-Jun-03 19:51 Toni78 4-Jun-03 19:51  You cannot access the LED of a floppy disk through software!!! It is an integral part of the floppy disk and it has nothing to do with the operating system. Maybe, you could flash the HDD LED (since the BIOS does it) but not that of a floppy. // Afterall I realized that even my comment lines have bugs Re: how to make Floppy-Disk-Device's LED blinking FlyingDancer4-Jun-03 20:13 FlyingDancer 4-Jun-03 20:13  Oh, Thanks. Now I have another question, could you help me? How can I carry out a Sequential-Verify test on floppy disk in VC? Thank you very much! LeonOrient Re: how to make Floppy-Disk-Device's LED blinking Toni784-Jun-03 20:51 Toni78 4-Jun-03 20:51  Sorry but I don't know. // Afterall I realized that even my comment lines have bugs Re: how to make Floppy-Disk-Device's LED blinking FlyingDancer4-Sep-03 15:12 FlyingDancer 4-Sep-03 15:12  Now I have made FDD's LED blinking as my special ratio the way is to access some special ports in addion, it requires to load a driver CFtpFileFind Bug ! oz_the_wizard3-Jun-03 21:52 oz_the_wizard 3-Jun-03 21:52  Hi~ Below source is that find a file on ftp server. (from MSDN example) By the way, no problem on windows iis ftp server , but finder.FindFile() always return 1 on unix server . What's wrong?? CInternetSession sess(_T("MyProgram/1.0")); CFtpConnection* pConnect = NULL; pConnect = sess.GetFtpConnection(_T("ftp.microsoft.com")); CFtpFileFind finder(pConnect); // start looping BOOL bWorking = finder.FindFile(_T("*")); // bug !! while (bWorking) { bWorking = finder.FindNextFile(); printf("%s\n", (LPCTSTR) finder.GetFileURL()); } There are two men, one is a programmer, another is a man. Making selected item bk 50% transparent in a ownerdrawn clistctrl justin2233-Jun-03 21:42 justin223 3-Jun-03 21:42  I got a ownerdrawn clistctrl that I have a bk image in. How do I make the selected item background color about 50% transparent (I want to blend it with the bkimage)? Re: Making selected item bk 50% transparent in a ownerdrawn clistctrl Cris4-Jun-03 4:38 Cris 4-Jun-03 4:38  In the CListCtrl::DrawItem(LPDRAWITEMSTRUCT) function, you can manage the CDC object for fill each item to transparent. I also need this implementation (with 100% transparent), and if you get please tell me how make it. []'s Cris. Special characters program meshteb3-Jun-03 21:35 meshteb 3-Jun-03 21:35  What the program actually does is that it searches an input file containing special characters contained in some words(i.e Ô , * and #352; ) .After finding such words it replaces those characters with this (i.e \o^ , \e^ and \sh respectively).I hope you will have the picture now. SPECIFICATION Deal with input or check whether input has the following special characters, i.e. read a file of text containing a list of words and check for the occurrence of these characters: Ô or ô * as used in the word "pôô" * or * - as used in the word "r*ma" #352; or #353; - as used in the word "le#353;a#353;a" If a word has any of these character replace each character by the following characters respectively: ô with \o^ * with \e^ #353; with \sh I would appreciate it if you could could have a short program to sort this issue out. Let me say that it should be like this: input -> words.doc pôô r*ma le#353;a#353;a aôwô b*thô output -> c:\output.txt p\o^\o^ r\e^ma le\sh;a\sh;a a\o^w\o^ b\e^th\o^ Yes the text file is ASCII format(that "#352;" represent an S with a cap on top).It is Northern Sotho language(South African language) Re: Special characters program Ted Ferenc3-Jun-03 21:55 Ted Ferenc 3-Jun-03 21:55  The simple way is to use a lookup table e.g. char lookup[256]; each element will contain the character that is to be displayed for relevent ASCII value e.g lookup[235] = '?'; The majority will probably be the "standard" ASCII values. So read in a buffer and use the look up table to convert each character, to a new or the same buffer; This solution is only really valid if there are a lot of mappings that change, otherwise it can be slow. If there are only a few use a simple case statement for the mapped characters. Of couse you could look at the ASSCII code chart and see if a simple mask would do the job, e.g. converting lower to upper case. If I have seen further it is by standing on the shoulders of Giants. - Isaac Newton 1676 Re: Special characters program Andrew Walker3-Jun-03 22:03 Andrew Walker 3-Jun-03 22:03  Can't think of an application to do this off the top of my head. However, if what you are looking for is API capable of doing exactly this you could start with: 1/ boost::regex[^] 2/ System.Text.RegularExpressions in the .NET framework The benefit of using boost::regex is that you get a little more flexibility. The benefit of using the .NET framework is you can code it in C# and it'll be about 1/4 the size. Converting _int64 to string Shah Shehpori3-Jun-03 21:04 Shah Shehpori 3-Jun-03 21:04  How can i convert _int64 to string? Normally whenever i need to convert numbers to string i use the following code: ************************************** int num = 123; std::string strNum; std::strstream strm; strm << num << std::ends; strNum = strm.str(); *************************************** This always works fine for me if the data type of a number is 'int' or 'float'. Today for the first time i need to convert an '_int64' number to string. I am using the code i described above but i get the following error: ServerMain.cpp(79) : error C2593: 'operator <<' is ambiguous Can anyone tell me the cause of problem and its solution

Last Visit: 31-Dec-99 18:00     Last Update: 25-Jun-24 23:43 Refresh ᐊ Prev1...14844148451484614847148481484914850148511485214853 Next ᐅ

General    News    Suggestion    Question    Bug    Answer    Joke    Praise    Rant    Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.