1.Explain bytecode, JVM ?

bytecode:The Java compiler does not translate your program into the machine language
for your particular computer. Instead, it translates your Java program into
a language called " byte-code".


JVM:Byte-code is not the machine language for any particular computer.Byte-code
is the machine language forfictitious computer called the "Java Virtual
Machine".

§.以上資料來自於課本

2.Explain class, object
class:是一種資料型態,它只是一些用來描述物件的屬性或功能,。Class是一種使用者自訂型別,
主要是用來彌補Java原生Data Type的不足

object:每個原生的資料型態都會有一個值，例如一個變數含一二進位值101，而Class 的資料
型態的變數的值就是object(物件)。物件包含了資料 與相關的操作程序。

3.Let i=2;
Print i;
Print 2 * (i++);
Print i;

public class work1
{
public static void main (String[] args)
{
int i=2;
int x;
System.out.println("i="+i);
x = 2*(++i);
System.out.println("2*(i++)="+x);
System.out.println("i="+i);
}
}

結果:
i=2
2*(++i)=4
i=3

4. Let i=2;
Print i;
Print 2 * (++i);
Print i;

public class work2
{
public static void main (String[] args)
{
int i=2;
int x;
System.out.println("i="+i);
x = 2*(++i);
System.out.println("2*(++i)="+x);
System.out.println("i="+i);
}
}

結果:
i=2
2*(++i)=6
i=3

5. Let m=7, n=2;
Print (double) m/n;
Print m/ (double)n;

public class work3
{
public static void main (String[] args)
{
double m1=7;
int n1=2;
double y;
y = m1/n1;
System.out.println("m1/n1="+y);
double m2=2;
int n2=7;
double z;
z= m2/n2;
System.out.println("m2/n2="+z);
}
}

結果:
m1/n1=3.5
m2/n2=0.2857142857142857