[OpenCV]How to get the number of camera [closed]

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The following is my code, but i find that it will make the memory leak

int CvCaptureCAM_DShow::getDeviceCount(){
int deviceNumber = VI.listDevices(true);
return deviceNumber;}


int  cvGetDeviceCount_DShow(){
CvCaptureCAM_DShow* capture = new CvCaptureCAM_DShow;

int deviceCount = capture->getDeviceCount();

delete capture;
capture = NULL;

return deviceCount;

}