// Programmer: Fazli Can - November 9, 2015

public class MyClass {

public static void main(String args[]) {

String testString = "ankara";
String ngramStr = ngram( testString, 0, 4);
System.out.println("ngram: " + ngramStr);

testString = "istanbul";
ngramStr = ngramCharByChar( testString, 0, 4);
System.out.println("ngram: " + ngramStr);

testString = "bilkent";

allNgrams (testString);

}

//============================================================

public static String ngram(String inString, int startNdx, 
                           int ngramLen)
{
   String resultStr;

   int strLen;

   strLen = inString.length( );

   resultStr = "";

   if ( startNdx + ngramLen <= strLen)
   {
      resultStr = inString.substring (startNdx, startNdx + 
                                      ngramLen);
   }

   return ( resultStr );

}

//============================================================


public static String ngramCharByChar(String inString, int startIndex, int ngramLen)
{
   String resultStr;

   int strLen;

   strLen = inString.length( );

   resultStr = "";

   // Create the ngram char by char.
   for( int i = startIndex; i < startIndex + ngramLen; i++ )
   {
      char nextChar = inString.charAt(i);
      resultStr = resultStr.concat( String.valueOf(nextChar) );
   } 

   return ( resultStr );
}

//============================================================

// Generate all possible ngrams of inString
public static void allNgrams (String inString)
{
    int inStringLen;
    
    inStringLen = inString.length( );
    
    for ( int ngramLength = 1; ngramLength <= inStringLen;
                                             ngramLength++ )
    {
        for ( int startIndex = 0; 
              startIndex + ngramLength <= inStringLen;   
              startIndex++ )
        {
            System.out.println ( ngram(inString, startIndex, 
            ngramLength) );
            System.out.println ( ngramCharByChar(inString, 
            startIndex, ngramLength) );
        }
    }
} // end of allNgrams ( )

} // end of MyClass definition