#include<iostream.h>
#include<string>

// findspaceInd("John Doe")  --> 4
int findspaceInd(string s)
{  int i;
   int answer;
   i = 0;
   answer = s.size();  // no space found
   while ( i<s.size()  && answer == s.size() )
     {
       if (s[i] == ' ') answer = i;
       i++;
     }  // while
   return answer;
} 
   
  /*
{  int i;
   i = 0;
   while (i<s.size() && s[i] != ' ')
     {  i++; }
   return i;  // if there's no space, i==s.size()
}
*/

  // substring("abcdefghi",3,40) --> "defg"
string substring(string s, int start, int length)
{  string answer;
   int i;   // loop counter
   answer = "";
   i = start;
   while (i<s.size() && i<start+length)
     {
       answer = answer + s[i];
       i++;
     } // while 
   return answer;
}

//            01234567
// firstname("John Doe") --> "John"
string firstname(string s)
{ int si;  // index of the space char
  string answer;
  si = findspaceInd(s);
  if (si == s.size())  // no space
    answer = s;
  else
    answer = substring(s,0,si);
  return answer;
}

string lastname(string s)
{ int si;  // index of the space char
  string answer;
  si = findspaceInd(s);
  if (si == s.size())  // no space
    answer = s;
  else
    answer = substring(s,si+1,s.size()-(si+1));
  return answer;
}

int main()
{
  cout << firstname("John Doe") << endl;
  cout << lastname("John Doe") << endl;
  return 0;
}