CODEWITHSUNDEEP
pascal
Inside Man
Inside Man

Reputation: 4297

Reversing a string in a recursive way

I want to reverse a string using a recursive function, here is my code:

Program InvertTheString;
var n:integer;word:string;

Function Invert (N:integer; word:string) : string;
begin
     if N=1 then
        Invert:=word[N]+Invert
     Else
        Invert:=Invert(N-1,word);
end;

BEGIN
readln(word);
n:=length(word);
writeln (Invert(N,word));

writeln;write('Press Enter To Exit...');
readln;
END.

But it is not working, where is worng?

Upvotes: 0

Views: 4531

Answers (3)

nidal mejai
nidal mejai

Reputation: 1

Function Invert (ch:string) : string;
begin
 if ch='' then
 Invert:=''
 else
 {get the last letter of the string + eliminate it and execute the function}
 Invert:=copy(ch,length(ch),1)+Invert(copy(ch,1,length(ch)-1));
end;

Upvotes: 0

rene
rene

Reputation: 42483

Function Invert (N:integer; word:string) : string;
begin
     if N=0 then
        Invert:=''
     Else
        Invert:= word[N] + Invert(N-1,word);
end;

Upvotes: 3

Ryan Stewart
Ryan Stewart

Reputation: 128899

I don't do Pascal, but a typical (simple) recursive reverse, in pseudo-code, looks like:

function reverse(word)
  if empty(word) return ""
  else return reverse(withoutFirstLetter(word)) + firstLetterOf(word)

Upvotes: 2

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