Widening conversion happens automatically no

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Widening conversion happens automatically. No information is lost. int i = 45; double d = i; 9 Automatic type promotion We have already seen that Java will automatically promote the smaller numeric type when an arithmetic operator is used on mixed types (e.g. adding an int and a double): 2.0 automatically promoted d 5.0 + 3.0 For example: double d; d = 2 + 3.0; 10 Explicitly converting between compatible types We can use a "cast" to force a conversion from one type to another. For example: the fractional part is truncated when the conversion takes place d i . 23 7 23 double d = 23.7; int i = (int) d; 11 Calling a Method Statements that end with () are method calls, e.g. System.out.println ( "Hello" ) ; static methods instance methods There are two types of methods in Java: We say that we are calling the println() method. 12 Using Static Methods A static method is a method that is called using the following form: ClassName . methodName ( list of values ) Math . random(); Math . max(a, b); Math . min(a, b); ClassName . methodName () For example: or
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CS101 Lecture 5 3 13 double x = Math.max(25.1, 13.5); The Math class The Math class contains many static methods which perform common mathematical functions, e.g. Math.min(int, int) Returns the greater of two values (either int or double). Returns the smaller of two values (either int or double). Math.max(int, int) For example: Math.min(double, double) Math.max(double, double) 25.1 14 double x = Math.pow(4, 2); The Math class continued Math.pow(double, double) Returns the first number to the power of the second number. Math.sqrt(double) Returns the square root of a double value. Math.random() Returns a random number between 0.0 and 1.0 (excluding 1.0). For example: 16.0 15 Math.random() Produces a random double value greater than or equal to 0.0 and less than 1.0 0.0 0.9999999 double d = Math.random(); For example: In this case, the variable, d, will store a number which is greater than or equal to 0.0 and less than 1.0.
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  • Summer '12
  • AdrianaFerraro
  • Computer Science, Order of precedence, String literal, public void

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