How do you extract the actual name of your input variable in a function?

I need to extract the actual name of my input variable for naming a file. Here is my simple script.

     function bmp=array2bmp(a)

     bmp=uint8(a);
     nam=strcat(varname(a),'.bmp');
     imwrite(bmp,nam,'bmp');

     end

and varname is a function defined as such

     function n=varname(var)

     n=inputname(1);

     end

so if I have an array named 'testbmp' and I type

     bmp=array2bmp(testbmp);

My output is a .bmp file named 'a.bmp' not 'testbmp.bmp'. This does not make sense to me. Is there a way I can call the actual name of my actual input variable instead of whatever dummy variable I wrote in the function?

Answer 1

[Geoff Hayes]

Alex - it does make sense since you are passing a variable named a into your function varname. To get the variable name testbmp, you would have to call inputname(1) from the within the function that "receives" this variable as an input I.e. array2bmp.

[Alex]

This worked. Thank you for your detailed explanation which helped me understand the reasoning behind the problem.

Answer 2

[Robert Cumming]

can you not just do this:

     function bmp=array2bmp(a)

     bmp=uint8(a);
     nam=strcat(inputname(1),'.bmp');
     imwrite(bmp,nam,'bmp');

You dont need your sub function varname