Variables and Assignment Statements

Read this chapter, which covers variables and arithmetic operations and order precedence in Java.

7. Calculation

Answer:
The first value was stored in a variable of data type long an integer type. Integers do not have fractional parts.
 The second forty was the result of a calculation involving a variable of data type double, a floating point type, 
 which does have a fractional part. (Here, the fractional part was zero.)

Calculation

public class Example
{
  public static void main ( String[] args )
  {
    long   hoursWorked = 40;    
    double payRate = 10.0, taxRate = 0.10;    

    System.out.println("Hours Worked: " + hoursWorked );
    System.out.println("pay Amount  : " + (hoursWorked * payRate) );
    System.out.println("tax Amount  : " + (hoursWorked * payRate * taxRate) );
  }
}

Look carefully at the statement highlighted in red. The parentheses around

(hoursWorked * payRate)

force the multiplication to be done first. After it is done, the result is converted to characters and appended to the string "pay Amount : ".

When you have a calculation as part of a System.out.println() statement, it is a good idea to surround the calculation with parentheses to show that you want it done first. Sometimes this is not necessary, but it does not hurt, and makes the program more readable.

Question 8:
Would it be better to write some of those statements on two lines instead one one?