How to plot this function

I want to plot y for x this equation.

y = 1/2 for x = 0

sin(pi*x/2)/(x*pi) for otherwise

So, I write this code. but It doesnt work. Help me friends.

x = -100:0.1:100;

if x == 0

y = 1/2;

else

y = sin(pi*x/2)/(x*pi);

end

plot(x, y);

Answer 1

[KSSV]

x = -100:0.1:100;
y = sin(pi*x/2)./(x*pi);
y(x==0) = 1/2 ; 
plot(x, y);

[O Kyung Kwon]

thx, bro

Answer 2

[Johannes Hougaard]

You need to use the element-wise multiplication/division (.* or ./) rather than the matrix based multiplication (* or /).

See also https://se.mathworks.com/help/matlab/ref/times.html

...and then do the zeroexemption afterwards

This code should do the trick:

x = -100:0.1:100;
y = sin(pi.*x/2)./(x.*pi);
y(x==0) = 1/2;
plot(x,y);

If you were to do it in a for loop (which I'd strongly disadvice, but it can be useful to know for other purposes) it would be:

x = -100:0.1:100;
y = ones(size(x)); %pre-allocating for speed
for ii = 1:length(x)
    if x(ii) == 0
        y(ii) = 1/2;
    else
        y(ii) = sin(pi.*x(ii)/2)./(x(ii).*pi);
    end
end
plot(x,y);

The for-loop is a tenfold slower and more complex...