How to code this in Matlab? Please help!

1. [Make line search subroutines.] Given the current iteration point zk R", a descent searching direction dk E Rn, and the subroutines to evaluate the function f(x) R R and gradient Vf(x) R for any point point E R", let o(a) := f(xk + ?d), make your own subroutines in Matlab (or other computer language you are familar) to find step size ?, which satisfies (a) an Armijo-type line search condition, that is to find ?k such that where 0