# MATLAB: Trouble with if statement

if

I am trying to write a statement that if r>n2 then i require an error message to be displayed otherwise i need it to continue on and carry out the rest of the algorithm. For examples which r<n2 the code works but for r>n2 the message is displayed but an error messages stating rep not assigned is also appearing. not sure what im doing wrong. any help appreciated. here is my code:
function [rep]=assign(B)[r,c]=size(B)           % dimension of matrix. r will be number of studentsW = B(:);               % produces matrix in one long vector n=length(W);             %total number of elements in matrixProjects2 = unique(W);   % identifies which projects were chosenn2=length (Projects2)   % number of projects chosenif r<n2,  [a,b]=hist(W,unique(W));             %                                z2=[a',b];                           % prodcuces a vector showing projects preferenced in second column and the number of times they have been preferenced  in first column  rep=sortrows(z2,1);                     %sorts matrix by number of repetitions else   disp(['Error: The number of students exceeds number of projects'])  returnendend

rep=[];
isempty(assign(x))