public class PrimitiveConversions {
    public static void main(String[] args) {

	byte someByte;
	int someInt;
	long someLong;
	float someFloat;
	double someDouble;

	//----------------------------------
	//Part I
	//Syntax for casting primitive types
	//----------------------------------

	//widening can be done implicitly
	someByte = 37;
	someInt = someByte;
	someFloat = someInt;

	//narrowing must be explicit (with cast)
	someInt = 37;
	// someByte = someInt;   compile-time error, cast needed
	someByte = (byte)someInt;  //correct


	//-----------------------------------------
	//Part II
	//Casting may result in loss of information
	//-----------------------------------------
	System.out.println("Casting may lose information...");

	System.out.println("Narrowing:");

        //ok: small int --> byte
	someByte = (byte)127;
	System.out.println("(byte)127 == " + someByte);

        //trouble: large int --> byte
        //High order bits are discarded, so result
        //may change magnitude and sign as well
	someByte = (byte)255;
	System.out.println("(byte)255 == " + someByte);

	//trouble: float-point-->integer
        //Decimals are lost
	someInt = (int)12.8f;
	System.out.println("(int)12.8f == " + someInt);

	//trouble: even when a floating point number appears
	//not to have decimals, they might be lurking
	someDouble = 4.56;
	someDouble = someDouble * 100;
	someInt = (int)(someDouble);
	System.out.println("(int)(4.56 * 100) == " + someInt); //prints 455
	//Explanation:
	//someDouble is actually 455.9999999999999609201495...
        //so someLong gets 455 (trimmed decimals), not 456

	System.out.println("Widening, which is implicit, is usually ok:");

	//ok: int --> long
	someLong = (long)5000034;
	System.out.println("(long)5000034 == " + someLong);

	//trouble: long --> float
	//A floating point number has fewer significant
	//digits than a long (7 vs 19)
	someInt = 1234567890;
	someFloat = 1234567890f;
	System.out.println("1234567890 - (int)1234567890f == " 
			   + (someInt - (int)someFloat));

    }
}