Ava Foundation Fourth day

1. Sort the bitwise operations, especially the left and right shifts (with or without symbols) to your blog.

The emphasis is on the operation process of clear negative numbers.

/*

Class Demo {

public static void Main (string[] arge) {

int a =-4; 1111 1100

int B = a >> 2; 1111 1111

int B = A >>> 2 0011 1111

System.out.println (b);

}

}

*/

/* 2.byte to hexadecimal string representation programming principles and implementation methods are organized into blogs.

Class Demo {

public static void Main (string[] arge) {

byte A = 28;

byte low = (Byte) (A & 0x0f);

byte hight = (byte) ((A & 0xf0) >>4);

Char[] Array = {' 0 ', ' 1 ', ' 2 ', ' 3 ', ' 4 ', ' 5 ', ' 6 ', ' 7 ', ' 8 ', ' 9 ', ' A ', ' B ', ' C ', ' D ', ' E ', ' F '};

System.out.println ("0x" + array[hight] + array[low]);

}

}

*/

3. Define a function to calculate the and of all elements of an integer array.

/*

Class Demo {

public static void Main (string[] arge) {

Int[] array = {2,3,5,10};

int sum = 0;

for (int a=0; a<array.length;++a) {

Sum+=array[a];

}

SYSTEM.OUT.PRINTLN (sum);

}

}

*/

4. Copy of the array.

Class Demo {

public static void Main (string[] arge) {

Int[] array = {2,3,5,10};

int[] Arrayback = new Int[array.length];

for (int a=0; a<arrayback.length;++a) {

Arrayback[a] = Array[a];

}

for (int a=0; a<arrayback.length;++a) {

System.out.print (Arrayback[a] + "");

}

}

}

5. Heap memory default is 1/4,

----------------------------------------

JAVA-XMX//Set heap memory max

-XMS//Set heap memory initial value

ClassName//class name

A: The default maximum heap memory is 1/4 of physical memory, when running a Java program, you can-xms the initial heap memory size,-XMX set the maximum heap memory size;

Ava Foundation Fourth day