Give a recursive algorithm in [Pascal style] pseudocode which computes the conca

Question

Give a recursive algorithm in [Pascal style] pseudocode which computes the concatenation of i copies of a string.

For example:

procedure concat(w = w1w2 . . .wn : string, i : nonnegative integer)
. . .
. . .
. . .

(v = v1v2v3 . . . is the concatenation of i copies of w)
return v

For two strings x = x1 . . . xk and y = y1 . . . y, use the pseudocode expression xy to refer to the concatenation of x and y.
For example, the assignment z := xy will result in z being the string x1 . . . xky1 . . . y.

THIS IS WHAT I HAVE SO FAR, IS IT CORRECT?

procedure concat(w = w1w2 . . .wn : string, i : nonnegative integer)

    if i:= 0 then

        v:=w

        return v

else if i1 then

    v:=concat(v+w, w, i-1)

    return v

end

Explanation / Answer

Not correct. One problem is that you call concat with three arguments and it can only take two arguments. Here is the correct answer -- I don't know the details of Pascal-style pseudocode but I'll just follow the style you've used and you can alter my answer if I've made any mistakes in details of style.

procedure concat(w = w1w2 . . .wn : string, i : nonnegative integer)

    if i:= 0 then

        v:= ""   // Zero copies of w is the empty string

        return v

else

    // Concatenate w i-1 times, then add on one more w

    v:= concat(w, i-1)

    v:= vw

    return v

end

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