Create a For Loop

Question

Ivy Shen 2018-9-12

评论： Ivy Shen 2018-9-15

Hi, the task is that:

S0 = 0;
S1 = S0+p1-q1-e1;
S2 = S1+p2-q2-e2;

and so on

p,q,and e are all known. I tried to write a for loop for it as following:

for i = 1:121
S(i) = S(i-1)+p(i)-q(i)-e(i);
S = S(i);
end

but S(i-1) gives S(0) which is not allowed in matlab.

Can anyone give me some advice on how to modify it to make it work?

Thank you!

Answer 1

James Tursa 2018-9-12

编辑：James Tursa 2018-9-12

Simply adjust your expectations of how to use indexing. E.g., let

S(1) mean the same thing as S0
S(2) mean the same thing as S1
etc

Then just adjust your indexing:

S(1) = 0;
for i = 2:122
    S(i) = S(i-1)+p(i)-q(i)-e(i);
end

Or, if the indexing of the p, q, e vectors already started at 1, then maybe this variation will work for you:

S(1) = 0;
for i = 2:122
    S(i) = S(i-1)+p(i-1)-q(i-1)-e(i-1);
end

Ivy Shen 2018-9-15

Thank you very much!