help for Image Edge Detection using Sobel

I wrote the code listed on this page but there was an error and I did not know the correct solution for it .
what the problem?
https://www.geeksforgeeks.org/matlab-image-edge-detection-using-sobel-operator-from-scratch/

[rawan alamri]

This is what appears when the code is applied

Error using imread>get_full_filename

File "[name of input image file].[file format]" does not exist.

Error in imread (line 371)

fullname = get_full_filename(filename);

Answer 1

[Image Analyst]

Try this:

grayImage = imread('coins.png');
subplot(1, 2, 1);
imshow(grayImage, [])
%impixelinfo
title('Original Image')
edgeImage = imgradient(grayImage, 'sobel');
subplot(1, 2, 2);
imshow(edgeImage, [])
%impixelinfo
title('Sobel Image')

Answer 2

[DGM]

You actually have to supply a filename to imread(). That's just a placeholder in the code.

% for example
A = imread('peppers.png');

[rawan alamri]

thank you so much.