creating function matlab code

How can write a function DFT(x) (in terms of jw) such that for the given discrete signal x[n]:

[Walter Roberson]

What is w in this context?

[Walter Roberson]

Is x[n] intended to indicate x multiplied by floor(n)? Because if it is intended to indicate indexing then you cannot index at infinity.

[geometry geometry]

no x[n] is a discrete type signal. and DFT is the Fourier transform of x[n]. (w is frequency variable)

[Guillaume]

A discrete transform is by definition over a finite discrete domain, not -∞, +∞.

The discrete fourier transform is the fft function in matlab. Is that what you're asking?

[geometry geometry]

I don't want to use fft. the signal x[n] is zero for large n. (for example we can assume that x[n]=0 for n<-100 and n>100).

the result of DFT should be in terms of w.

[Guillaume]

I think you need to explain in a lot more details what it is you're after. Perhaps, give some concrete examples.

I don't want to use fft. Why not? This gives you the frequencies (ω) of your discrete signal.

[geometry geometry]

I'm going to plot DFT.

Because my project says to do it without using fft.