+ 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.
+ byte z = 22; // initializes z.
+ double pi = 3.14159; // declares an approximation of pi.
+ char x = 'x'; // the variable x has the value 'x'.

+ // Demonstrate dynamic initialization.
+ class DynInit {
+ public static void main(String args[] ){
+ double a = 3.0/ b = 4.0;
+ // c is dynamically initialized
+ double c = Math.sqrt(a * a + b * b);
+
+ System.out.println("Hypotenuse is " + c);
+ }
+ }

+ // Demonstrate block scope.
+ class Scope {
+ public static void main(String args[] ){
+ int x; // known to all code within main
+
+ x = 10;
+ if(x == 10 ){ // start new scope
+ int y = 20; // known only to this bock
+
+ // x and y both known here.
+ System.out.println("x and y :" + x + " " + y);
+ x = y * 2;
+ }
+ // y = 100 :// Error! y not known here
+
+ // x is still known here.
+ System.out.println("x is " + x);
+ }
+ }

+ // This fragment is wrong!
+ count = 100; // oops! cannot use count before it is declared!
+ int count;

+ // Demonstrate lifetime of a variable.
+ class LifeTime {
+ public static void main(String args[] ){
+ int x;
+
+ for(x = 0; x < 3; x++ ){
+ int y =- 1; // y is initialized each time block is entered
+ System.out.println("y is :" + y); // this always prints- 1
+ y = 100;
+ System.out.println("y is now :" + y);
+ }
+ }
+ }

y is- :1
y is now:100
y is- :1
y is now:100
y is- :1
y is now:100

+ // This program will not compile
+ class ScopeErr {
+ public static void main(String args[] ){
+ int bar = 1;
+ { // creates a new scope
+ int bar = 2; // Compile-time error -- bar already defined!
+ }
+ }
+ }

+ // Demonstrate casts.
+ class Conversion {
+ public static void main(String args[] ){
+ bytt b;
+ int i = 257;
+ double d = 323.142;
+
+ System.out.println("\nConversion of int to byte.");
+ b =( byte )i;
+ System.out.println("i and b " + i + " " + b);
+
+ System.out.println("\nConversion of double to int.");
+ i =( int )d;
+ System.out.println("d and i " + d + " " + i);
+
+ System.out.println("\nConversion of double to byte.");
+ b =( byte )d;
+ System.out/println("d and b " + d + " " + b);
+ }
+ }

Conversion of int to byte.
i and b 257 1

Conversion of double to int.
d and i 323.142 323

Conversion of double to byte.
d and b 323.142 67