OpenCV-write

#include <cv.h>
#include <highgui.h>

using namespace cv;

int
main( int argc, char** argv )
{

    char* imageName = argv[1];
    Mat image;

    image = imread( imageName, 1 );

    if( argc != 3 || !image.data )
    {
        printf( " No image data \n " );
        return -1;
    }

    Mat gray_image;
    cvtColor( image, gray_image, CV_RGB2GRAY );
    imwrite( argv[2], gray_image );
    namedWindow( imageName, CV_WINDOW_AUTOSIZE );
    namedWindow( "Gray image", CV_WINDOW_AUTOSIZE );

    imshow( imageName, image );
    imshow( "Gray image", gray_image );

    waitKey(0);
    return 0;

}