I have a for loop code to calculate matrix multiplication. What is missing?

I want to create a code that calculates y=A*x for two matrices. I wrote a code from how a school book suggested and I'm stuck and don't now where to go from here. I get s=0 four times in a row. The dimensions are right but obviously not the answer. I have defined A and x but nothing is happening. What am I doing wrong?

 A=[1 5 9;2 6 10;3 7 11;4 8 12];
  x=[1;1;1];

y=zeros(4,1);
for i=1:4
    s=0
    for j=1:3
        s=s+A(i,j)*x(j);
    end
    y(i)=s;
end

Answer 1

[Matt J]

Just add a semicolon to this line

s=0

The code is working fine, otherwise.

[Britney]

Ahh the semicolon trap it was. Thank you for the quick answer.