undefined reference to `cv::VideoCapture::VideoCapture(cv::String const&)'

The error "undefined reference to cv::VideoCapture::VideoCapture(cv::String const&)' " typically occurs when the linker is unable to find the definition for theVideoCapture` constructor from the OpenCV library. This error can often be resolved by linking the OpenCV library correctly in your C project.

To fix this error, you need to ensure that you have linked the OpenCV library correctly. You can do this by adding the appropriate linker flag to your build command.

For example, if you are using the g++ compiler, you can add the following linker flag to your build command:

g++ your_file.cpp -o your_program `pkg-config --cflags --libs opencv`

Alternatively, if you are using a different compiler or build system, you may need to consult the documentation or configuration files to determine how to correctly link the OpenCV library.

Make sure you have installed OpenCV and have the necessary include files and libraries in your project. Double-check that you have included the correct headers in your source file:

#include <opencv2/opencv.hpp>

Also, ensure that the OpenCV library is correctly linked during the compilation process. You can do this by adding the appropriate linker flags to your build command or by configuring your build system to link the OpenCV library.

Once you have made these changes, try compiling and running your program again. The "undefined reference" error should be resolved, and you should be able to use the VideoCapture class from the OpenCV library without any issues.