showing error This still showing error like... Error in imshow (line 198) [common_ar​gs,specifi​c_args] = ... Error in' roi_demo (line 31) imshow(spr​intf('C:\U​sers\shrad​dha\Docume​nts\MATLAB​\Snaps\%d.​png',k)) >>'

using the code which you gave me for dynamic image name is showing error

This still showing error like...

Error in imshow (line 198) [common_args,specific_args] = ...

Error in roi_demo (line 31) imshow(sprintf('C:\Users\shraddha\Documents\MATLAB\Snaps\%d.png',k)) >>

Answer 1

[Geoff Hayes]

Shraddha - you should include the complete error message when posting your question. Looking at your code, if I were to try and run just

 k        = 2;
 filename = sprintf('C:\Users\shraddha\Documents\MATLAB\Snaps\%d.png',k);

the warning message

 Warning: Control Character '\U' is not valid. See 'doc sprintf' for control characters valid in the format
string.

is generated and the filename is simply

 filename =
    C:

Your string is a path to a file which includes backslashes. The backslash is a control character for fprintf and sprintf, so if you wish your string to have this character then you have to re-write your sprintf as

 k        = 42;
 filename = sprintf('C:\\Users\\shraddha\\Documents\\MATLAB\\Snaps\\%d.png',k);

Now, your filename will be correct

 filename =
    C:\Users\shraddha\Documents\MATLAB\Snaps\42.png

Answer 2

[Image Analyst]

You can either use double backslashes like Geoff showed:

imshow(sprintf('C:\\Users\\shraddha\\Documents\\MATLAB\\Snaps\\%d.png',k))

or use forward slashes. Yes, Windows handles forward slashes just fine:

imshow(sprintf('C:/Users/shraddha/Documents/MATLAB/Snaps/%d.png',k))

I still think that either one of those is bad form - too complicated. Personally I and Geoff recommend getting the filename in advance. It will make the code simpler to read and to maintain. I'd do it this way:

folder =  'C:\Users\shraddha\Documents\MATLAB\Snaps\';
baseFileName =  sprintf('%.png',k);
fullFileName = fullfile(folder, baseFileName);
if exist(fullFileName , 'file')
    imshow(fullFileName);
else
    warningMessage = sprintf('Warning: %s does not exist', fullFileName);
    uiwait(warndlg(warningMessage));
end