Mega Code Archive
0023 Declaring a Variable
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In Java, all variables must be declared before they can be used. The basic form of a variable declaration is shown here:
type identifier [ = value][, identifier [= value] ...] ;
type could be int or float.
identifier is the variable's name.
Initialization includes an equal sign and a value.
To declare more than one variable of the specified type, use a comma-separated list.
int a, b, c; // declares three ints, a, b, and c.
int d = 3, e, f = 5; // declares three more ints, initializing d and f.
The following variables are defined and initialized in one expression.
public class Main {
public static void main(String[] argv) {
byte z = 2; // initializes z.
double pi = 3.14; // declares an approximation of pi.
char x = 'x'; // the variable x has the value 'x'.
}
}
Variable cannot be used prior to its declaration.
public class Main {
public static void main(String[] argv) {
count = 100; // Cannot use count before it is declared!
int count;
}
}
Compiling the code above generates the following error message:
D:\>javac Main.java
Main.java:4: cannot find symbol
symbol : variable count
location: class Main
count = 100; // Cannot use count before it is declared!
^
1 error
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