Trapezoidal integration without trapz function

Hi, I have many data points that make a curve and I want to find the area under the curve using the trapezoidal integration rule but without using the trapz function matlab has. Can you please help me.

[John D'Errico]

Why is it a problem if you use trapz or not? If it is, then this must be homework. But you need to do your homework. That is why it was assigned to you, not to us.