Using OpenCV in eclipse - c++

Question

I am trying to setup opencv in eclipse Luna. I have written a sample application as follows :
#include <cv.h>
#include <highgui.h>
#include<iostream>
using namespace cv;
int main( int argc, char** argv )
{
Mat image;
image = imread( argv[1], 1 );
if( argc != 2 || !image.data )
{
printf( "No image data \n" );
return -1;
}
namedWindow( "Display Image", CV_WINDOW_AUTOSIZE );
imshow( "Display Image", image );
waitKey(0);
return 0;
}
In my project properties i have included /usr/local/include/opencv in (Project->Properties->C/C++ Build->Settings->Tool Settings -> GCC C++ Compiler -> Includes -> Include Paths. )
and /usr/local/lib in (Project->Properties->C/C++ Build->Settings->Tool Settings -> GCC C++ Linker -> Libraries -> Library Search Path. )
My output of the command pkg-config --cflags opencv is -I/usr/local/include/opencv -I/usr/local/include
and the output of pkg-config --libs opencv is
-L/usr/local/lib -lopencv_stitching -lopencv_superres -lopencv_videostab -lopencv_viz -lopencv_adas -lopencv_bgsegm -lopencv_bioinspired -lopencv_ccalib -lopencv_datasets -lopencv_face -lopencv_latentsvm -lopencv_objdetect -lopencv_line_descriptor -lopencv_optflow -lopencv_reg -lopencv_rgbd -lopencv_saliency -lopencv_stereo -lopencv_surface_matching -lopencv_text -lopencv_tracking -lopencv_xfeatures2d -lopencv_shape -lopencv_video -lopencv_ximgproc -lopencv_calib3d -lopencv_features2d -lopencv_ml -lopencv_flann -lopencv_xobjdetect -lopencv_xphoto -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_photo -lopencv_imgproc -lopencv_core -lopencv_hal
When I tried building my project i got the following errors.
‘imread’ was not declared in this scope
‘imshow’ was not declared in this scope
‘namedWindow’ was not declared in this scope
‘waitKey’ was not declared in this scope
Function 'imread' could not be resolved
Function 'imshow' could not be resolved
Function 'namedWindow' could not be resolved
Function 'waitKey' could not be resolved
Can anyone help me fixing the problem and explain what is that I was missing.

Answer 1

Try to change:
#include <cv.h>
#include <highgui.h>
To this:
#include <opencv2/opencv.hpp>
You also need to link the Libraries (GCC C++ Linker » Libraries):
opencv_core
opencv_imgcodecs
opencv_highgui
You didn't say which version you are using, but as you have -lopencv_imgcodecs, you are probably using OpenCV 3. If you prefer, follow the instructions here. Also change from CV_WINDOW_AUTOSIZE to WINDOW_AUTOSIZE.