I can't use int for functions

I use Matlab R2016a. I write a function but I can't use int to get integrate:

function y=g1(x)
if x>0
    y=1;
else
    y=-1;
end
end

and when I run :" int(g1) " I receive this error :

int(g1)
Not enough input arguments.

Error in g1 (line 2)
if x>0

what should I do. please help step by step because I am beginner.

[Stephen23]

Related question:

https://www.mathworks.com/matlabcentral/answers/322397-parse-error-at-usage-might-be-invalid-matlab-syntax

Answer 1

[Star Strider]

Your ‘g1’ is a function, so you have to pass it the argument you wrote it to evaluate. The integral function does this implicitly (so you do not actually see it).

I would use the integral function, not the Symbolic Math Toolbox int function (unless you have to do this symbolically):

g1 = @(x) (x>0).*(1) + (x<=0).*(-1);

a = -pi;
b =  pi;
Result = integral(g1, a, b);

I used ‘logical indexing’ to define ‘g1’ here. It is more efficient.