How to do inverse tranform in dice throw simulate?

Hi so I'm trying to simulated loaded dice throw and do a inverse transform, here's my code so far:

a = [0.125 0.125 0.125 0.125 0.125 0.125 0.125 0.125];

cdf = cumsum(a);

u = rand(); % assume u = 0.5

b = sum(cdf <= u) + 1

What should I do next for the inverse transform, and do I need a for loop?

[Torsten]

number_on_dice = find(u<cdf,1,'first');

Does that help ?

[Sherman Ng]

So apparently the question is only asking for the u's and b's so I do not have to compute the list of s. Apparently I need a for-while-loop to fill in values of u and b. How should I do the for-while loop though?