in the previous definition of a class, it is generally the structure of a base class (virtual base class or pure virtual base class) plus a derived class. the veteran programmer told me that like Microsoft COM, we should first declare some interface cla...
1. Under folder A, there is a folder B 2. Generate static libraries in folder B, assuming that the ld.a, source code is written in C 3. The .CPP file in folder A, a function that references the source code in folder B, and links to the static library ...
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We usually new an object, and the process of requesting memory is completed by operator new, so how does allocator in stl take over operator new to complete the memory request? How is the memory request right of an object transferred? I don t think oper...
We all know that polymorphisms in CPP depend on virtual tables and virtual pointers, so when are virtual tables generated? Is it before or after the constructor is executed? And where are the virtual watches stored? ...
I have created a shared folder in the solution. In the project that needs to use the files in the shared file holiday, right-click-add-existing items-select files in the shared folder-select add as a link. Although the addition was successful, when I ref...
Under RT,linux, how to troubleshoot a CPP service with high CPU and memory? Trouble a little bit and hope to give a more detailed answer. At present, all I can think of is gdb, but I m not quite sure how to get gdb. ...
Club * ClubMgr::GetClub(clubid_t nClubId) const { for (std::map<userid_t, std::map<clubid_t, Club* > >::const_iterator it1 = m_hashClubs.begin(); it1 != m_hashClubs.end(); PPit1) { std::map<clubid_t, Club* >::const_itera...
wrote the class template of the chain stack, saved it as the header. h file, and designed a simple addition, subtraction, multiplication and division calculator based on this. In the process of compilation, the following error occurred. I don t know h...
Why not provide semaphores directly in RT,CPP11? Instead, it can be implemented jointly with mutexes and conditional variables, for what consideration? ...
void MainWindow::fileCreateActionSlot() { QLineEdit *line_edit=new QLineEdit(); line_edit->setGeometry(50,50,80,80); line_edit->setText(""); QLabel my_label; my_label.setText(""); } ...
class class1 { public: friend void Print(class1 &a, class2 &b); }; class class2 { public: friend void Print(class1 &a, class2 &b); }; this is the problem. I have a function that has objects of two classes in its parameters, and...
1, on VS2015, after using the CPPMFC dialog box to edit and define the variable, the function body DoDataExchange is empty and no DDX_Text call statement is generated. 2. The problem is like a problem. I don t know what s going on. ...
-sharpinclude <stdio.h> struct{ unsigned int widthValidated; unsigned int heightValidated; }status1; struct{ unsigned int widthValidated : 1; unsigned int heightValidated : 1; }status2; int main(void){ printf("Memory siz...
there is a set of numbers, for example, 3, requires that the sum equal to 3 is selected from this group of numbers (3 added numbers). For example, the three added numbers cannot be the same (for example, 1: 1, 1: 1), and there is no order requirement fo...
when learning < random > library, only seed_seq does not quite understand although I went to MSDN, and cppreference, it is not very clear that there is too little information about seed_seq on Google. my understanding is: when a given seed is not ve...
requirements: play two audio files at the same time (duration: one long and one short). Playback requirements: as shown in the figure: Audio file 1 plays normally, and the total length of the file is greater than the set playback duration Audio...
ask a weak question. int x = 10; x += (xPP)+x; cout << x << endl; 32 my understanding is x = x + (xPP) + x = 31. Should it be understood as x = (xPP) + (xPP) + x or x = x + (xPP) + (xPP)? is it true that the addition o...
problem description: in learning the knowledge of the CPP template, the program uses last to represent the last position of the saved table item, and during initialization, the last=-1, is initialized to an empty table (my understanding is that there i...
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the js code is as follows: function send() { var xml = new XMLHttpRequest(); xml.onreadystatechange = function () { if(xml.readyState==4 & xml.status==200){ if(xml.responseText== true ){ ...
upSingleImg: function () { var that = this; wx.uploadFile({ url: url, filePath: that.data.arrImg[i], name: image , formData: { ... }, success: f...
carries access_token and refresh_token in the header when requesting the interface. if access_token expires, the new access_token will be obtained according to refresh_token , and then the expiration time of refresh_token will be updated! ...
6. Make sure that the url you get for signature is obtained dynamically. For the dynamic page, see how php is implemented in the example code. If the static page of html sends url to the backend for signature through ajax, the frontend needs to use js t...
if($url = www.xxx.com ){ header( HTTP 1.1 301 Moved Permanently ); header( Location: $target_url); } the above code, 301 redirect has been accessed in the browser, and the browser will remember that it is permanently redirected. Will direc...