Pravilan jezik (S-N)

#include <iostream>
using namespace std;

bool slog(char a, char b)
{
     bool c, d;

     if (a=='a' || a=='A' || a=='e' || a=='E' || a=='i' || a=='I' || a=='o' || a=='O' || a=='u' || a=='U')
         c = true;
     else
         c = false;

     if (b=='a' || b=='A' || b=='e' || b=='E' || b=='i' || b=='I' || b=='o' || b=='O' || b=='u' || b=='U')
         d = true;
     else
         d = false;

     if ((c==true && d==false)||(c==false && d==true))
     return true;
     else return false;
}

void provjeri(string k)
{
     bool p = true, c = true;
     if (k=="a" || k=="i" || k=="o" || k=="u")
          p = true;
     else if (k=="e")
          cout << k << endl;
     else
     {
         if (k.length()%2==0)
         {
            if (k[0]=='a' || k[0]=='A' || k[0]=='e' || k[0]=='E' || k[0]=='i' || k[0]=='I' || k[0]=='o' || k[0]=='O' || k[0]=='u' || k[0]=='U')
               p = false;
            else
                for(int i=0; i<k.length(); i=i+2)
                {
                        if (slog(k[i], k[i+1])==false)
                        {
                           p = false;
                           break;
                        }
                }
         }
         else
         {
             if (k[0]=='a' || k[0]=='A' || k[0]=='e' || k[0]=='E' || k[0]=='i' || k[0]=='I' || k[0]=='o' || k[0]=='O' || k[0]=='u' || k[0]=='U')
               c = false;

             if(c==true)
             p = false;

             for(int i=1; i<k.length(); i=i+2)
            {
                    if (slog(k[i], k[i+1])==false)
                    {
                       p = false;
                       break;
                    }
            }
         }
     }

     if (p==false)
         cout << k << endl;
}

main()
{
      string s, k="";

      getline(cin, s);
      s = s + " ";

      for (int i=0; i<s.length(); i++)
      if ((s[i]<=122 && s[i]>=97)||(s[i]<=90 && s[i]>=65))
         k = k + s[i];
      else
      {
          if (k!="")
             provjeri(k);
          k="";
      }

      system("PAUSE");
}