writing condition function with vector

Write a function which inputs a vector v and outputs a vector with the indices i which represent a sign change in v.

Write a function which inputs a vector v and outputs a vector with the indices i which represent a sign change in v.

One suggestion is to write conditions on the vector and some kind of shifted version of itself.

please help me writing this function code

[Rik]

This is your homework assignment. What have you tried so far yourself?

[David Hill]

Look at what this does:

v<0;%turns your vector into ones and zeros.

look at diff() and find() commands.

Answer 1

[Nishant Gupta]

You can use the followoing logic for writing the function:

x = [1 2 -3 4 -5 -6 7 -9];
product = x(1:end-1).*x(2:end);
res = find(product<0) + 1;

[Rik]

@Nishant: it is generally discouraged to post fully working solutions for homework assignments. You can leave this one, since the OP probably already received the complete code in the email alert.

Your code is also shadowing the prod function.