You need to learn and understand cell array indexing.
cellarray(indices)
returns a cell array made of the cells in indices,e.g:
c1 = c2([1 3 5]) %return a cell array made of cells 1, 3 and 5 of c2
c1 = c2(3) %return a cell array made of 1 cell: cell 3 of c2
whereas,
cellarray{index}
returns the content of the cell at index.
You want the content of the cell, so use curly braces:
fprintf('Current Scheme, %s\n',protocol{pno}); %you may also want a '\n' in your string
