the piecewise function runs out a weird figure

function codes are as this

function f = myfun(x)

if (x<1);
    
f=x.^2 ;

else
    f=x;
end

end

main program codes are as this

clc;
clear all;
close all;

x=0:0.1:10;

y=myfun(x);

plot(x,y)

a simple figure but a queer figure,why

[Adam Danz]

Hint from

doc if

"An expression is true when its result is nonempty and contains only nonzero elements (logical or real numeric)."

Answer 1

[Voss]

x=0:0.1:10;
y=myfun(x);
plot(x,y)

function f = myfun(x)
idx = x < 1;
f = zeros(size(x));
f(idx) = x(idx).^2;
f(~idx) = x(~idx);
end