opencv sample code run time error using argv[] - visual-studio-2010

Question

I run this sample cod, and i get run time exception
#include "stdafx.h"
#include <iostream>
using namespace std;
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"
using namespace cv;
int _tmain(int argc, char** argv)
{
//IplImage* img = cvLoadImage( "Walk1001.jpg" ,1 );
IplImage* img =cvLoadImage( argv[1] );
if(!img)
cout << "Could not open or find the image" << endl ;
cvNamedWindow( "Example1", 1 );
cvShowImage( "Example1", img );
cvWaitKey(0);
cvReleaseImage( &img );
cvDestroyWindow( "Example1" );
return 0;
}
when i use IplImage* img = cvLoadImage( "Walk1001.jpg" ,1 ); instead of this IplImage* img =cvLoadImage( argv[1] ); program runs fine. but otherwise i got error.
What is to do with argv. i have came across many programs in which image is loaded through some argv[] syntex! how to use this array (argv[]) or what else?

Answer 1

to use the argv array, you've got to supply arguments to your program (from the cmdline, or similar)
prog.exe Walk1001.jpg 19
now argv holds 3 elements, [ "prog.exe", "Walk1001.jpg", "19" ], and argc==3
in your program , do:
char * imgPath="Walk1001.jpg"; // having defaults is a good idea
if ( argc > 1 ) // CHECK if there's actual arguments !
{
imgPath = argv[1]; // argv[0] holds the program-name
}
int number = 24;
if ( argc > 2 ) // CHECK again, if there's enough arguments
{
number = atoi(argv[2]); // you get the picture..
}
sidenote: you seem to be a beginner (nothing wrong with that!), the opencv api has changed over the years, please don't use IplImage* and cv*Functions(the 1.0 api),
use cv::Mat and functions from cv:: namespace.
using namespace cv;
int main(int argc, char** argv)
{
char * imgPath="Walk1001.jpg";
if ( argc > 1 )
{
imgPath = argv[1];
}
Mat img = imread( imgPath );
if ( img.empty() )
{
cout << "Could not open or find the image" << endl ;
return 1;
}
namedWindow( "Example1", 1 );
imshow( "Example1", img );
waitKey(0);
// no, you don't have to release Mat !
return 0;
}

Answer 2

I am getting run time exception. the error is line 2482 unknown function in array.cpp? I think i get this message from imshow after debugging. I'm using Mat img=imread("walk100.jpg"); but the img.total() returning NULL. why imread is returning NULL. cvload is working perfectly.
I got this solved, on the web i came to know about ***d.dll. while adding dll files, I omitted the d, that is for release mode not for debug mode. So I just place "d", like opencv_core244d.dll instead of opencv_core244.dll
thanks all for your contribution