"@" inside fzero command. I get an erro why?

I've got 2 .m files. The line which calls the second file is 

[f1 q] = fzero(@avaliator,const.guessf1,const) 
it'll call avaliator (.m file) 

function q = avaliator

e = -100 ;
[r,y] = integrator(const);
q = sqrt((y(end,2)/const.Total_mass)^2 + (r(end)^e/const.Total_Radius)^2)*(y(end,2).../const.Total_mass) ;

the problem is that it only calls avaliator if I take the "@" out. I think it's because of "@" is for calling functions right? But in another code very similar to this "@" is used with no problem and the .m file called is not a function but something like this avaliator file I posted. Does anyone know why it's returning an error? (suppose all the const.'something' known)

Answer 1

[Matt J]

It's because avaliator is not written to accept an input argument. It needs to be.

function q = avaliator(x)

    q=%do something with x

[Douglas Alves]

I actually put function q = avaliator(const) in order to const be recognized when it comes in avaliator. But it's not recognized either. I should've put [] between const.guessf1 and const anyways. But it doesn't change anything. lol I think I've got multiples errors here..