writing convolution function in matlab?

It is basically assignment. I have to make a MATLAB function to systematically develop the sequence y[n] generated by the convolution of the

two-finite length sequence x[n] and ?[?]. Program should be able to handle causal and non- casual sequences.

Program should call for the input sequences and their indices vectors .

Below is my code

function [ny,y  ] = convolution(nx,x,nh,h )
%UNTITLED7 Summary of this function goes here
%   Detailed explanation goes here
a=nx(1)+nh(1)  %nx is time span of x and nh is time span of h
b=nx(length(x))+nh(length(h))
ny=[a:b]% ny is length of y
y=conv(x,h)
end

Please kindly guide me and correct me,if my code is not as per requirment/question?

[Image Analyst]

Are you allowed to use the built-in conv() function in your assignment to create a convolution function?

[ABTJ]

Yes. But i dont understand ,how to do the part"Program should be able to handle causal and non- casual sequences.

Program should call for the input sequences and their indices vectors ." ??

[Image Analyst]

It's when you slide the filter along the signal, whether the half of the filter that deals with later (future) time indexes should be zeroed out or not. If they're zeroed out then "future" times won't affect the filtered signal value.

[ABTJ]

What is meant by"indices vector" here?Is it meaning time indexes,which i have denoted by nh and nx in my function?

[Matt J]

That's a question for the person who gave you the assignment.