UVa 494 Kindergarten Counting Game

UVa 494 Kindergarten Counting Game

Tha task of this problem is to count the number of words of one line.
My solution is to insert a space into the beginning of the line.
Here is my code:

#include < stdio.h >
#include < iostream >
#include < string >
using   namespace  std;
bool  letter( char  c)
{
     if ((c >= ' a ' && c <= ' z ' ) || (c >= ' A ' && c <= ' Z ' ))
         return   true ;
     return   false ;
}

int  ans;
string  s;

int  main()
{
     /*
    freopen("data.in","r",stdin);
    freopen("data.out","w",stdout);
    // */

     while (getline(cin,s))
    {
        ans = 0 ;
        s.insert( 0 , "   " );
         for ( int  i = 0 ;i < s.length() - 1 ;i ++ )
             if ( ! letter(s[i]) && letter(s[i + 1 ]))
                ans ++ ;
        cout << ans << endl;
    }
return   0 ;
}