c語言--有幾個常用的自己寫的函數(shù),每次也要重寫,應如何處理??

把文件名改成**.h (**是自己命名的)

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以后只要在頭文件加

#include"**.h"就可以了

""表示先從當目錄找

表示先從庫找

看你把文件放在哪而定

怎樣用C語言重寫FILE的庫函數(shù)，比如重寫fopen(),fgetc(),fclose(),fseek(),printf().

這最好找個專業(yè)的，一般人是沒辦法寫的，一是難度大，二是這么費事沒報酬也不好找著

找百度能找著無疑是大海撈針，最好去專業(yè)點的平臺去找

C語言為什么可以重寫標準庫函數(shù)?

這個問題是一個好問題，我之前也沒思索過或者嘗試過，

首先我們弄清楚一件事，函數(shù)聲明可以放在任何頭文件，實現(xiàn)可以放在任何實現(xiàn)該函數(shù)的源文件中，那么就存在一個問題：

編譯時，到底優(yōu)先去使用哪一個，為什么沒有把標準庫中的函數(shù)擴展過來；在windows下標準庫被編譯成了msvcr120.dll(msvcr100.dll，這里指release版)，所以并不是擴展到代碼中，而是在調用時動態(tài)鏈接；

而題主在其中自定義文件中實現(xiàn)了該函數(shù)，所以編譯時找到了該函數(shù)的實現(xiàn)，并不會去鏈接dll（這應該是編譯器做的一些工作，確定系統(tǒng)的dll需要加載哪些），所以題主的程序執(zhí)行時就只有一份fputc了，并不沖突。

題主可以通過快捷鍵跳轉聲明就知道了，VS下，點選fputc實現(xiàn)函數(shù)按F12跳轉到聲明，指向的是stdio.h，再按一次跳轉到你自己的定義了。Qt的話使用F2。

大概就是這樣子了，可追問。

哪位大神能用c語言 重寫opencv 的下面6個函數(shù)？？或者從源碼中整理出來，可以編譯，運行？？

去git上面看看源碼

//先說一下這個函數(shù)吧

//cvNamedWindow

CV_IMPL?int?cvNamedWindow(const?char*?name,?int?flags){????

CV_FUNCNAME("cvNamedWindow");????

if?(!name)CV_ERROR(CV_StsNullPtr,?"NULL?name");????

HighguiBridge::getInstance().namedWindow(name);????

return?CV_OK;????

}???

//而它又需要HighhuiBridge這個類，它有個單例工廠方法

HighguiBridge?HighguiBridge::getInstance(){????

static?HighguiBridge?instance;????

return?instance;????

}

//上面2個函數(shù)實際調用這2個成員函數(shù)

CvWindow*?HighguiBridge::namedWindow(cv::String?name)?{

CvWindow*?window?=?HighguiBridge::getInstance().findWindowByName(name.c_str());

if?(!window)window?=?createWindow(name);

return?window;

}

//創(chuàng)建窗口先是查找有沒有已有窗口

CvWindow*?HighguiBridge::findWindowByName(cv::String?name){

auto?search?=?windowsMap-find(name);

if?(search?!=?windowsMap-end())return?search-second;

return?nullptr;

}

//如果沒有會用這個函數(shù)創(chuàng)建

CvWindow*?HighguiBridge::createWindow(cv::String?name){

CvWindow*?window?=?new?CvWindow(name);

windowsMap-insert(std::paircv::String,?CvWindow*(name,?window));

return?window;

}

//創(chuàng)建窗口是CvWindow類

class?CvWindow{????

public:????

CvWindow(cv::String?name,?int?flag?=?CV_WINDOW_NORMAL);????

~CvWindow();????

/**?@brief?NOTE:?prototype.????

Should?create?button?if?there?is?no?button?with?this?name?already.????

*/????

void?createButton(cv::String?name);????

/**?@brief?Creates?slider?if?there?is?no?slider?with?this?name?already.????

The?function?creates?slider?if?there?is?no?slider?with?this?name?already?OR?resets????

provided?values?for?the?existing?one.????

*/????

void?createSlider(cv::String?name,?int*?val,?int?count,?CvTrackbarCallback2?on_notify,?void*?userdata);????

/**?@brief?Updates?window?image.????

@param?src?Image?data?object?reference.????

The?function?updates?window?image.?If?argument?is?null?or?image?control?is?not?found?-?does?nothing.????

*/????

void?updateImage(CvMat*?arr);????

/**?@brief?Returns?reference?to?the?trackbar(slider)?registered?within?provided?window.????

@param?name?Name?of?the?window.????

The?function?returns?reference?to?the?trackbar(slider)?registered?within?provided?window.????

Returns?nullptr?if?trackbar?with?specified?name?is?not?found?or?window?reference?is?nullptr.????

*/????

CvTrackbar*?????findTrackbarByName(cv::String?name);????

Page^???????????getPage();????

private:????

cv::String?name;????

//?Holds?image?data?in?CV?format????

CvMat*?imageData;????

//?Map?of?all?sliders?assigned?to?this?window????

std::mapcv::String,?CvTrackbar**??sliderMap;????

//?Window?contents?holder????

Page^?page;????

//?Image?control?displayed?by?this?window????

Image^?imageControl;????

//?Container?for?sliders????

Panel^?sliderPanel;????

//?Container?for?buttons????

//?TODO:?prototype,?not?available?via?API????

Panel^?buttonPanel;????

//?Holds?image?width?to?arrange?other?UI?elements.????

//?Required?since?imageData-width?value?gets?recalculated?when?processing????

int?imageWidth;????

//?Default?markup?for?the?container?content?allowing?for?proper?components?placement????

static?const?Platform::String^?markupContent;????

//?Default?Slider?size,?fallback?solution?for?unexpected?edge?cases????

static?const?double?sliderDefaultWidth;????

};????

//CvWindwo構造函數(shù)為

CvWindow::CvWindow(cv::String?name,?int?flags)?:?name(name){

this-page?=?(Page^)Windows::UI::Xaml::Markup::XamlReader::Load(const_castPlatform::String^(markupContent));

this-sliderMap?=?new?std::mapcv::String,?CvTrackbar*();

sliderPanel?=?(Panel^)page-FindName("cvTrackbar");

imageControl?=?(Image^)page-FindName("cvImage");

buttonPanel?=?(Panel^)page-FindName("cvButton");

//?Required?to?adapt?controls?to?the?size?of?the?image.

//?System?calculates?image?control?width?first,?after?that?we?can

//?update?other?controls

imageControl-Loaded?+=?ref?new?Windows::UI::Xaml::RoutedEventHandler(

[=](Platform::Object^?sender,

Windows::UI::Xaml::RoutedEventArgs^?e){

//?Need?to?update?sliders?with?appropriate?width

for(auto?iter=sliderMap-begin();iter!=sliderMap-end();++iter){

iter-second-getSlider()-Width?=?imageControl-ActualWidth;

}

//?Need?to?update?buttons?with?appropriate?width

//?TODO:?implement?when?adding?buttons

});

}