merged lab01g

src/lec01/glab/MoreDownCasting.java

+package lec01.glab;
+
+/**
+ * Created by Adam on 10/4/2015.
+ */
+public class MoreDownCasting {
+
+    public static void main(String[] args) {
+
+
+        System.out.println("integer values");
+        //try the following 259, 132, 128
+        short sResult = 132;
+        byte yResult = (byte) sResult;
+        System.out.println(yResult);
+
+        System.out.println("float values");
+
+        //double to float downcasting
+        double lValue1 = 0.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000012;
+        double lValue2 = 101.6546465465464321351654313465123168768546134650646546546546546545645645646545646546546546545646546654564654646546540303212;
+        float fValue1 = (float)lValue1;
+        float fValue2 = (float)lValue2;
+
+
+        System.out.println(String.valueOf(lValue1));
+        System.out.println(String.valueOf(fValue1));
+
+
+
+        System.out.println(String.valueOf(fValue2));
+        System.out.println(String.valueOf(lValue2));
+
+
+        System.out.println("trucate and then round");
+        //truncate by casting to int
+        System.out.println((int)  lValue2);
+        //round by rounding
+        System.out.println(Math.round(lValue2));
+
+
+
+    }
+}

src/lec01/glab/PostFix.java

+package lec01.glab;
+
+/**
+ * Created by Adam on 10/5/2015.
+ */
+public class PostFix {
+
+    public static void main(String[] args) {
+
+        //postfix and prefix these
+        int nC = 0;
+        while (nC < 10){
+            System.out.println(nC++);
+        }
+
+    }
+}

src/lec01/glab/PromotionAndCastingPrimitives.java

@@ -6,6 +6,44 @@ public class PromotionAndCastingPrimitives {
 	 * @param args
 	 */
 	public static void main(String[] args) {
+	
+		
+		double dOperand1 = 5.897;
+		int nOperand2 = 8;
+		
+		//promotion works when:
+		//there are two operands of different primtive types; the smaller precision operand will get promoted to larger precision operand
+		double dResult = dOperand1 / nOperand2; //here nOperand2 is promoted to double
+
+		//integer division - will truncate, not round!
+		int nResultIntDivision =  23/ 8;
+
+
+
+		//the primitive result on the left of the assignment operator is of greater precision than the result of the right expression
+		//in this case, the result of integer division is 2.66666 trucated to 2, then the result is assigned as (2.0)
+		float fResult = nOperand2 / 3;
+
+		//you concatenate a string with a primitive, the primitive is promoted to a string
+		String strResult = "Hello" + dOperand1;
+
+		System.out.println("nResultIntDivision: " +nResultIntDivision);
+		System.out.println("dResult: " +dResult);
+		System.out.println("fResult: " +fResult);
+		System.out.println("strResult: " +strResult);
+		
+		//you can downcast a primitive. 
+		//upcasting happens automatically; it's called promotion and you lose no precision
+		//downcasting loses precsion
+		
+		int nAnswer1 = (int)56.9356974;
+		
+		//long lAnswer1 = Math.max(3.856, 98798798);
+		long lAnswer1 = Math.max((long)3654.856, 568211);
+		//you must cast and casting primitives sometimes loses precision
+		
+		System.out.println(nAnswer1);
+		System.out.println(lAnswer1);
 
         //BASIC RULES OF INTEGER DIVISION
         //keep in mind that integer division produces a TRUNCATED result, not rounded