Решение задачи String 68

#include <bits/stdc++.h>

using namespace std;

int main()
{
    string  s, a;
    a =  char(int('a') - 1) + "";
    cin >> s;
    for(int i = 0; i < s.size(); ++i){
        if(s[i] >= 'a' && s[i] <= 'z')
            if(s[i] > a[a.size() - 1])
                a += s[i];
            else{
                cout << i;
                return 0;
            }
    }
    cout << 0;
    return 0;
}

program String68;
 
const
   LowerCase = ['a'..'z'];
 
var
   Line            : string;
   Counter, Result : byte;
   Spare           : char;
 
begin 
   writeln('Enter a string of letters and numbers: ');
   readln(Line);
   Counter := 1;
   Spare   := chr(ord('a') - 1);
   Result  := 0;
   while (Counter <= Length(Line)) and (Result = 0) do
      begin
         if (Line[Counter] in LowerCase) then
            if (Line[Counter] > Spare) then
               Spare := Line[Counter]
            else
               Result := Counter;
         inc(Counter);
      end;
   writeln('The element number breaking the sequence is ', Result);
end.