Ví dụ thực tế về cách sử dụng Biến, Kiểu Dữ liệu trong Java

            int a,b,c;

float pi;

double d;

char a;
        

            pi =3.14f;

do =20.22d;

a=’v’;
        

            int a=2,b=4,c=6;

float pi=3.14f;

double do=20.22d;

char a=’v’;
        

            class Niit2019 {

    static int a = 1; //static variable
    int data = 2019; //instance variable 
    void method() {
        int b = 90; //local variable  
    }
}
        

            byte (1 byte)
short (2 bytes)
int (4 bytes)
long (8 bytes)
        

            float (4 bytes)

double (8 bytes)
        

            char (2 bytes)
        

            boolean (1 byte) (true/false)
        

            double d;
int i = 10;
d = i;
        

            double d = 10;
int i;
i = (int) d;
        

            class Demo {
 public static void main(String args[]) {
  byte x;
  int a = 270;
  double b = 128.128;
  System.out.println("int converted to byte");
  x = (byte) a;
  System.out.println("a and x " + a + " " + x);
  System.out.println("double converted to int");
  a = (int) b;
  System.out.println("b and a " + b + " " + a);
  System.out.println("\ndouble converted to byte");
  x = (byte)b;
  System.out.println("b and x " + b + " " + x);
 }
}
        

            int converted to byte
a and x 270 14
double converted to int
b and a 128.128 128

double converted to byte
b and x 128.128 -128