Big decimal

src/main/java/com/amigoscode/_1_beginners/_1_thebasics/Variables.java

@@ -11,27 +11,33 @@ public class Variables {
     public static void main(String[] args) {
 
         // TODO: 1 - Declare an int variable called age and assign it the value 25
-
+        int age = 25;
 
         // TODO: 2 - Declare a double variable called price and assign it the value 9.99
-
+        double price = 9.99;
 
         // TODO: 3 - Declare a boolean variable called isJavaFun and assign it the value true
-
+        boolean isJavaFun = true;
 
         // TODO: 4 - Declare a String variable called name and assign it your name
-
+        String name = "Jose";
 
         // TODO: 5 - Declare a char variable called grade and assign it the value 'A'
-
+        char grade = 'A';
 
         // TODO: 6 - Print all the variables above using System.out.println
         // Hint: You can print each variable on its own line, e.g.:
         //   System.out.println("Age: " + age);
-
+        System.out.println("Age: " + age);
+        System.out.println("Price: " + price);
+        System.out.println("isJavaFun: " + isJavaFun);
+        System.out.println("Name: " + name);
+        System.out.println("Grade: " + grade);
 
         // TODO: 7 - Declare a final (constant) variable called MAX_SCORE, set it to 100, and print it
         // Hint: Use the 'final' keyword before the type to make a constant
+        final int MAX_SCORE = 100;
+        System.out.println("MAX_SCORE: " + MAX_SCORE);
 
     }
 }

src/main/java/com/amigoscode/_2_developers/_8_bigdecimal/BigDecimalExercises.java

@@ -23,7 +23,7 @@ public static BigDecimal createFromString(String value) {
         // TODO: 1 - Create and return a BigDecimal using new BigDecimal(value).
         //  The String constructor preserves the exact decimal value.
         //  NEVER use new BigDecimal(0.1) — see TODO 6 for why.
-        return null;
+        return new BigDecimal(value);
     }
 
     /**
@@ -36,7 +36,7 @@ public static BigDecimal createFromString(String value) {
     public static BigDecimal addValues(BigDecimal a, BigDecimal b) {
         // TODO: 2 - Use the add() method to add a and b. Return the result.
         //  Remember: BigDecimal is immutable, so add() returns a NEW BigDecimal.
-        return null;
+        return a.add(b);
     }
 
     /**
@@ -48,7 +48,7 @@ public static BigDecimal addValues(BigDecimal a, BigDecimal b) {
      */
     public static BigDecimal multiplyValues(BigDecimal a, BigDecimal b) {
         // TODO: 3 - Use the multiply() method to multiply a and b. Return the result.
-        return null;
+        return a.multiply(b);
     }
 
     /**
@@ -63,7 +63,7 @@ public static BigDecimal divideValues(BigDecimal a, BigDecimal b, int scale) {
         // TODO: 4 - Use a.divide(b, scale, RoundingMode.HALF_UP) to divide.
         //  You MUST specify a rounding mode for division, otherwise you may get
         //  an ArithmeticException for non-terminating decimals (like 1/3).
-        return null;
+        return a.divide(b, scale, RoundingMode.HALF_UP);
     }
 
     /**
@@ -80,7 +80,7 @@ public static int compareValues(BigDecimal a, BigDecimal b) {
         // TODO: 5 - Use a.compareTo(b) to compare the two values.
         //  Return the result (which will be -1, 0, or 1).
         //  Do NOT use equals() for numeric comparison!
-        return 0;
+        return a.compareTo(b);
     }
 
     /**
@@ -94,6 +94,12 @@ public static void demonstrateDoubleProblem() {
         //  Print both values. Notice that fromDouble is NOT exactly 0.1!
         //  It will show something like 0.1000000000000000055511151231257827021181583404541015625
         //  Print a message explaining why the String constructor should be preferred.
+        System.out.println("The string constructor should be preferred because passing in a double\n " +
+                "causes the 0.1 to actually be 0.1000000000000000055511151231257827021181583404541015625 because\n" +
+                "it is essentially a floating point number based on binary fractions (base 2).\n" +
+                "Passing it through the BigDecimal constructor will allow it to do it's job exactly as it's meant to\n" +
+                "which is storing that exact long number into memory.");
+
 
     }