Шпоры по МПиПА / Строки / Взятие подстроки / Pascal / Исходник / substring

Program SubString;
const
Nmax = 10000;
type
MyString = array[0..Nmax-1] of char;
var
s: MyString;
first : integer;
last : integer;

function getSubstring(var str: MyString; var first, last : integer) : MyString;
var
Res : MyString;
i : integer;
begin
if ( ( first > last ) or ( last > length( str ) ) ) then begin
if first > last then begin
Res := ''; Write(' first position must be <= last position ');
end else begin
Res := ''; Write(' last position must be < length(str) ');
end;
end
else begin
for i := 0 to last - first do begin
Res[i] := str[first + i];
end;
end;
getSubstring := Res;
end;

begin
Writeln('Substring program.');
Write('Enter string: '); Readln(s);
Write('Enter first: '); Readln(first);
Write('Enter last: '); Readln(last);
Write('Your substring: '); writeln( getSubstring(s,first,last) );
Writeln('Press any key to continue...');
Readln;
end.