Help with Huffman Coding for MPEG Encoder

Hello guys, I have a problem with my so-called Huffman encoding MATLAB code. Instead of using the built-in functions (ie huffmandict, huffmanenco, huffmandeco), I am using for-loops to do the encoding and decoding. This is because it will be easier to translate into C later on. I have a predefined table of what each symbol should be. After compiling the code below, the output was all zeros, which made no sense to me. What I'm trying to do is convert 0 into 0, 1 into 10, so on and so forth so that it becomes a bitstream. Am I making any sense? What am I doing wrong here? Any help is greatly appreciated.

Symbol

0 ---> 0

1 ---> 10

2 ---> 110

3 ---> 1110

4 ----> 1111

Here's what I've got so far in terms of loops:-

[M,N] = size(a);
% Where a is the image matrix after quantization

for i = 1:M
    for j = 1:N
        if(a(i,j)==0)
            k(1,j) = 0;

          else if (a(i,j)==1)
                  k(1,j:j+1) = 10;

              else if (a(i,j) ==2)
                      k(1,j:j+2) = 110;

                  else if (a(i,j) ==3)
                          k(1,j:j+3) = 1110;

                      else
                          k(1,j:j+3) = 1111;
                      end
                  end
              end
          end
      end
  end