What exactly does this OpenCV program do? - visual-c++

Question

I want to know exaclty what this program does:
#include <iostream>
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
using namespace std;
int main(int argc, char* argv[])
{
printf("Hello world\n");
IplImage *img = cvLoadImage("C:/Program Files/OpenCV/samples/c/lena.jpg");
// Create a window
cvNamedWindow( "result",
CV_WINDOW_AUTOSIZE // allow window to resize to fit image true size
);
cvShowImage( "result", img ); // Show image in window already created
// Wait for a keystroke. If a positive argument is given, it will wait for
// that number of milliseconds and then continue. If 0 is given, the
// program will wait indefinitely for a keypress.
cvWaitKey(0);
// Clean up (not really necessary, but good programming practice)
cvReleaseImage( &img );
cvDestroyWindow("result");
system("PAUSE");
return EXIT_SUCCESS;
}
The reason i'm asking is because I think that a picture is supposed to pop up when I run the program but instead for me, a grey box pops up.
Can someone please shed some light on this problem of mine? Thanks in advance.

Answer 1

It loads an image
Shows the image
then wait for anykey (0)
On anykey press
frees the memory used and return EXIT_SUCCESS
It should work correctly, probably that the path isn't right
try to copy your image in your working folder and execute from there while removing the full path in your image address
"lena.jpg"
Also another option would be to try backward slashes
"C:\\Program Files\\OpenCV\\samples\\c\\lena.jpg"
EDIT *
You should run the diagnosis tests included with openCV
they are located in the opencv\bin directory and should be able to check if your installation is correct or not

Answer 2

#include <stdio.h>
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
int main(int argc, char* argv[])
{
printf("Hello world\n");
IplImage *img = cvLoadImage("fruits.jpg",1);
// Create a window
cvNamedWindow( "result",
CV_WINDOW_AUTOSIZE // allow window to resize to fit image true size
);
cvShowImage( "result", img ); // Show image in window already created
// Wait for a keystroke. If a positive argument is given, it will wait for
// that number of milliseconds and then continue. If 0 is given, the
// program will wait indefinitely for a keypress.
cvWaitKey(0);
// Clean up (not really necessary, but good programming practice)
cvReleaseImage( &img );
cvDestroyWindow("result");
system("PAUSE");
return EXIT_SUCCESS;
}
Makefile (Make sure u have tab instead of 8 spaces!)
CFLAGS=-g -Wall
test = test
$(test): $(test).c
gcc -ggdb `pkg-config opencv --cflags --libs` -g -c -Wall $(test).c -o $(test).o
gcc -ggdb `pkg-config opencv --cflags --libs` -lpthread -lm $(test).o -o $(test)
clean:
#echo Removing generated files...
rm -f $(test).o $(test)
This program works for me! Best Regards, Virgoptrex! Tested on OpenCv 1.0 on Ubuntu 8.10!