The following program demonstrates how each value in the expression gets promoted
to match the second argument to each binary operator:
class Promote {
public static void main(String
args[]) {
byte b = 42;
char c = 'a';
short s = 1024;
int i = 50000;
float f = 5.67f;
double d = .1234;
double result = (f * b) + (i
/ c) - (d * s);
System.out.println((f * b) +
" + " + (i / c) + " - " + (d * s));
System.out.println("result =
" + result);
}
}
Let's look closely at the type promotions that occur in this line from the program:
double result = (f * b) + (i / c) - (d * s);
In the first subexpression, f * b, b is promoted to a float and the result of the subexpression
is float. Next, in the subexpression i / c, c is promoted to int, and the result is of type int. Then,
in d * s, the value of s is promoted to double, and the type of the subexpression is double.
Finally, these three intermediate values, float, int, and double, are considered. The outcome
of float plus an int is a float. Then the resultant float minus the last double is promoted to
double, which is the type for the final result of the expression.
Arrays
An array is a group of like-typed variables that are referred to by a common name. Arrays of
any type can be created and may have one or more dimensions. A specific element in an array
is accessed by its index. Arrays offer a convenient means of grouping related information.
NOTE If you are familiar with C/C++, be careful. Arrays in Java work differently than they do in
OTE
those languages.
One-Dimensional Arrays
A one-dimensional array is, essentially, a list of like-typed variables. To create an array, you first
must create an array variable of the desired type. The general form of a one-dimensional
array declaration is
type var-name[ ];
Here, type declares the base type of the array. The base type determines the data type of each
element that comprises the array. Thus, the base type for the array determines what type of
data the array will hold. For example, the following declares an array named month_days
with the type "array of int":
int month_days[];
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