dimensions - reshape in MATLAB -

if come following line of code in matlab:

reshape(dataset{i},1, 200*200); 

• here, dataset{j} seems element in cell array. right? since using reshape, can that element array?
• when use reshape, define dimensions (i.e; m,n). in code above, m=1 , n=200*200? but, why wasn't n written 400 instance? there reason writing in syntax see?

thanks.

dataset cell array can't assume dataset{j} array. reshape work on strings , cell arrays well:

reshape({1,2,3,4},2,2)  ans =      [1]    [3]     [2]    [4]  >> reshape('abcd',2,2)  ans =  ac bd 

there's not obvious reason write 200*200 unless 200 important understanding being computed.