Substring algorithm

Question

Can someone explain to me how to solve the substring problem iteratively?

The problem: given two strings S=S₁S₂S

Answer 1

It would go something like this:

m==0? return true
cs=0
ct=0
loop
    cs>n-m? break
    char at cs+ct in S==char at ct in T?
    yes:
        ct=ct+1
        ct==m? return true
    no:
        ct=0
        cs=cs+1

end loop
return false