class Find
{
	// this class solves problem P5.24 in the textbook
	// in two ways:  one with recursion, one without.

	// this method looks for the string 't' inside
	// the supposedly larger string 's'
	public static int find( String s, String t )
	{
		int si=0, ti=0;
		while( si <= s.length() - t.length() )
		{
			// look inside String s, at position si
			String partOfS = s.substring( si, si+t.length() );
			                     // start ^^, ^^^^^^^^^^^^^ pastEnd

			if( partOfS.equals( t ) )  // compare strings
				return si;  // found at position si

			si++;
		}
		return -1;  // not found
	}

	// this method looks for the string 't' inside
	// the supposedly larger string 's'
	public static int findRecursive( String s, String t )
	{
		if( s.length() < t.length() )
			return -1;  // base case, s is too small; not found

		// look at first part of S
		String firstPartOfS = s.substring( 0, t.length() );

		// check if String s starts off with String t
		if( firstPartOfS.equals( t ) )  // compare strings
			return 0;  // found at position 0 of s
		else {
			// Recurse by removing first character from s,
			// and looking for t in the remainder of s.
			// If we found it, we must find the position in
			// s by counting as the recursion unrolls.
			int found = findRecursive( s.substring(1), t );
			if( found < 0 )
				return -1;  // didn't find it, keep -1
			else
				return 1+found;  // count the positions
		}
	}

	public static void main( String[] args ) {
		// use 4 simple test cases.  more should be used.
		// first case:  returns 1, the first match (multiple matches)
		// second case:  returns 0, matching at beginning of s
		// third case:  returns 9, matching at end of s
		// fourth case:  returns -1, no match

		System.out.println( find( "Mississippi", "is" ) );
		System.out.println( find( "Mississippi", "Miss" ) );
		System.out.println( find( "Mississippi", "pi" ) );
		System.out.println( find( "Mississippi", "hip" ) );

		System.out.println( findRecursive( "Mississippi", "is" ) );
		System.out.println( findRecursive( "Mississippi", "Miss" ) );
		System.out.println( findRecursive( "Mississippi", "pi" ) );
		System.out.println( findRecursive( "Mississippi", "hip" ) );
	}
}