2011-07-01 JAVA

1.http://www.ithome.com
   code review(程式碼審查)
   Design Pattern

class MyP5_66 {
     public static void main(String[] args) {
          System.out.println(Float.toHexString(3.75f));
   
     }

}
---------------------------------------------------------------------------
// 顯示關係運算子、相等運算子、邏輯否定運算子所產生的值

import java.util.Scanner;

class BooleanTester {

    public static void main(String[] args) {
        Scanner stdIn = new Scanner(System.in);

        System.out.print("整數a："); int a = stdIn.nextInt();
        System.out.print("整數b："); int b = stdIn.nextInt();

        System.out.println("a <  b  = " + (a <  b));
        System.out.println("a <= b  = " + (a <= b));
        System.out.println("a >  b  = " + (a >  b));
        System.out.println("a >= b  = " + (a >= b));
        System.out.println("a == b  = " + (a == b));
        System.out.println("a != b  = " + (a != b));
        System.out.println("!(a==0) = " + !(a == 0));
        System.out.println("!(b==0) = " + !(b == 0));
    }
}
------------------------------------------------------------------------------------
import java.util.Scanner;
class MyP6_5 {
     public static void main(String[] args) {
          Scanner stdIn = new Scanner(System.in);
         
          System.out.print("元素數:");
          int n = stdIn.nextInt();
          int[] a = new int[n];
         
          for (int i = 0; i < n ; i++) {
              System.out.print("a[" + i + "] = ");
              a[i] = stdIn.nextInt();
             
          }
          System.out.print("a = {");
          for (int i = 0 ; i < n-1; i++)
              System.out.print(a[i] + ",");
             
              System.out.println(a[n-1]+"}");
   
     }


}
---------------------------------------------------------------------------
// 求出並顯示陣列所有元素的總和（強化型for敘述）

class ArraySumForIn {

    public static void main(String[] args) {
        double[] a = { 1.0, 2.0, 3.0, 4.0, 5.0 };

        for (int i = 0; i < a.length; i++)
            System.out.println("a[" + i + "] = " + a[i]);

        double sum = 0;        // 總和
        for (double i : a)
            sum += i;

        System.out.println("所有元素的總和為" + sum + "。");
    }
}
---------------------------------------------------------------------------------------
// 以1、2、3、4、5初始化陣列的各個元素後顯示

class IntArrayInit {

    public static void main(String[] args) {
        int[] a = {1, 2, 3, 4, 5};
        a = new int[] {10,20,30,40,50};
        for (int i = 0; i < a.length; i++)
            System.out.println("a[" + i + "] = " + a[i]);
    }
}
--------------------------------------------------------------------------------
// 輸入陣列所有元素的值並顯示

import java.util.Scanner;

class IntArrayScan {

    public static void main(String[] args) {
        Scanner stdIn = new Scanner(System.in);

        System.out.print("元素數：");
        int n = stdIn.nextInt();            // 輸入元素數
        int[] a = new int[n];                // 產生陣列

        for (int i = 0; i < n; i++) {
            System.out.print("a[" + i + "] = ");
            a[i] = stdIn.nextInt();
        }

        for (int i = 0; i < n; i++)
            System.out.println("a[" + i + "] = " + a[i]);
    }
}
-----------------------------------------------------------------------------
// 因輸出回列首而改寫顯示完成的字元

class CarriageReturn {

    public static void main(String[] args) {
        System.out.print("ABCDEFGHIJKLMNOPQRSTUVWXYZ");
        System.out.println("\r12345\\");
    }
}
------------------------------------------------------------------------------------
// 從0.0開始遞增0.001至1.0為止，並且顯示其總和（以float控制迴圈）

class FloatSum1 {

    public static void main(String[] args) {
        float sum = 0.0F;

        for (float x = 0.0F; x <= 1.0F; x += 0.1F) {
            System.out.println("x = " + x);
            sum += x;
        }
        System.out.println("sum = " + sum);
    }
}

2011-06-30 JAVA

1.http://javaclubtw.blogspot.com/
2.windows 記憶體配置

3.Linux記憶體配置

4. int   4bytes  * 8 = 32bits
    long 8bytes * 8 = 64bits
    char 2bytes * 8 = 16bits
    boolean 2bytes * 8 = 16bits    
    float 4bytes * 8 = 32bits
    double 8bytes * 8 = 64bits
--------------------------------------------------------------------------
 class MyP5_60 {
         class static void main(String[] args) {
                 long x = 10; //10為int,casting(改型)
           
      

        }


}
--------------------------------------------------------------------

 class MyP5_60 {




class static void main(String[] args) {



long x = 2148000000L; //預設為int,compiler錯誤;加L則OK!





System.out.println("Long整數測試: " + x);





}



}