Sample code to load GrayScale image using Opencv

LoadGrayScaleImage.c

#include <iostream>
#include <cv.h>
#include <highgui.h>
  
using namespace std;
char key;
int main()
{
  IplImage* frame=cvLoadImage("img1.png",CV_LOAD_IMAGE_GRAYSCALE); //Load image in IplImage frame.
  cvNamedWindow("window1", CV_WINDOW_AUTOSIZE); //Create window of name 'Window1'
 
if(frame == NULL){   //if image file not found then print this message
 printf("the file doesnot exist");
 exit(0); 
}
 
cvShowImage("window1",frame);  //Display image in Window1
cvWaitKey(); //Wait for keyboard input
cvDestroyWindow( "window1" ); //destroy window
return 0;
}