Function Pointer As Struct Member

Function pointer as struct member - with arguments:

#include <stdio.h>

struct aritmathic{
    int a;
    int b;
    int (*add)(int, int);
    int (*subtract)(int, int);
    int (*multiply)(int, int);
};

int Add(int a, int b){
    return (a+b);
}

int Subtract(int a, int b){
    return (a-b);
}

int Multiply(int a, int b){
    return (a*b);
}

int main(){

    struct aritmathic ar;
    ar.a = 4;
    ar.b = 5;

    ar.add = Add;
    ar.subtract = Subtract;
    ar.multiply = Multiply;

    int a = ar.add(ar.a, ar.b);
    int b = ar.subtract(ar.a, ar.b);
    int c = ar.multiply(ar.a, ar.b);   

    printf("%d\n%d\n%d", a, b, c);

    return 0;
}

Simpler version for above:

#include <stdio.h>

struct aritmathic{
    int a;
    int b;
    int (*add) (struct aritmathic*);
    int (*subtract) (struct aritmathic*);
    int (*multiply) (struct aritmathic*);
};

int Add(struct aritmathic* ar){
    return (ar->a + ar->b);
}

int Subtract(struct aritmathic* ar){
    return (ar->a - ar->b);
}

int Multiply(struct aritmathic* ar){
    return (ar->a * ar->b);
}

int main(){

    struct aritmathic ar;
    ar.a = 4;
    ar.b = 5;

    ar.add = Add;
    ar.subtract = Subtract;
    ar.multiply = Multiply;

    int a = ar.add(&ar);
    int b = ar.subtract(&ar);
    int c = ar.multiply(&ar);   

    printf("%d\n%d\n%d", a, b, c);

    return 0;
}

Function Pointer As Struct Member

Below is a simple example of function pointer as a member of struct:

#include <stdio.h>

struct data{
    void(*hello)();
};

void hello(){
    puts("Hello comes from C");
}

int main(){

    // the first way
    struct data d;
    d.hello = hello;
    d.hello();

    // the alternate way
    struct data dd;
    struct data* ptr = &dd;
    ptr->hello = *hello;
    ptr->hello();
  
    return 0;
}

Better Looking Search Box

<div id="search">
    <form>
         <input type="text" id="text"/>
         <input type="submit" id="submit" value="Search"/>
     </form>
</div>

<style>

#search{
     border: 1px solid #ccc;
     max-width: -moz-fit-content;
     padding: 1px;
     -moz-border-radius: 5px;
}
#text{
     border: 0px solid #ccc;
     -moz-border-radius: 5px 0px 0px 5px;
     padding-left: 10px;
}
#submit{
     background: #88f;
     color: #fff;
     font: 14px arial;
     font-weight: bold;
     border: 0px solid #000;
     padding: 1px 5px;
     -moz-border-radius: 0px 5px 5px 0px;
     cursor: pointer;
}
#submit:hover{
     background: #55f;
}
form{
     margin: 0px;
     padding: 0px;
}

</style>

The result:

Better Looking Search Box

SSL - Generate RSA Key

To simply generate rsa key to stdout in default 512

OpenSSL> genrsa

For 1024

OpenSSL> genrsa 1024

For saving it to file

OpenSSL> genrsa -out mykey.pem 1024

To generate public RSA key, use
OpenSSL> rsa -in mykey.pem -pubout

Read more on here

SSL - Generate RSA Key

OpenSSL Introduction

To encrypt a text file use:

OpenSSL> enc -base64 -in myfile.txt

or
OpenSSL> enc -base64 -in myfile.txt -out myfile.txt.enc
or just a test using pipe
D:\git\bin>echo "Hello World" | openssl enc -base64
To decrypt, use
OpenSSL> enc -base64 -d -in myfile.txt.enc
To decrypt from pipe, use
D:\git\bin>echo "encrypted" | openssl enc -base64 -d
Learn more on here

OpenSSL Introduction

YUI - Starting

Introduction

Here's a sample for how to start using YUI framework.
First, linking for the API

Code:

<script src="http://yui.yahooapis.com/3.3.0/build/yui/yui-min.js" charset="utf-8"></script>

Second, make your control

Code:

<input type="text" id="ac-input"/>

Third, write the code

Code:

<script>
YUI.use('autocomplete', function(Y){
        Y.one('#ac-input').plug(Y.Plugin.AutoComplete, {
            source: ['apple','amazon','air','america']
    });
});
</script>

YUI - Starting

CSS - Advanced

Introduction

Here's some code that show some advanced of CSS that is practical for use.

Rounded Box

It's easy to make a rounded box. Even you don't need use image for it.

Code

<div>You don't need image for making box looks like rounded</div>

<style>
div{
    border: 1px solid #af0;
    padding: 5px;
    -moz-border-radius: 4px;
    -webkit-border-radius: 4px;
    border-radius: 4px;
}
</style>

The result will be:

You don't need image for making box looks like rounded

CSS - Advanced

GAE - Template

Introduction

Template makes your life easier. it separating between code logic of your program to what should display on the browser. Here's I just show up what the crucial template case that not handled by Django documentation.

Displaying List of Articles

It's really some often occurance for us to display item list. It's like blog post that consits of title, date, and content. Or it like personal data that consists of name, email, address and more. Here's for example we has some blog post:

Data Content

Title	Content
GAE Template	GAE Template is use Django template system. So when you are accustomed for using Django, it's good for you.
GAE Runtime	There are two available runtime for you. The first is Java and the second is Python. Whatever you choose, it should based on your preference for the language and your current skills.
GAE Datastore	In GAE, your data is saved in database, but you never handle it directly, because Google Datastore that handles it, and in all your time, you handle the datastore. The operation for data in datastore is like in native sql, but it's more abstract than it that is called GQL - Google Query Language.

For example you want to display the data on the home page, what you need is you main the logic code that retrieves the data using Google datastore query.

Program code: main.py

from google.appengine.ext import webapp
from google.appengine.ext.webapp.util import run_wsgi_app
from google.appengine.ext import db
from google.appengine.ext.webapp import template

class Blog(db.Model):     title = db.StringProperty()
    content = db.TextProperty()

class MainPage(webapp.RequestHandler):
    blog = Blog()
    query = db.GqlQuery("SELECT * FROM Blog")
    data = []
    for row in query:
        mapp = {}
        mapp['title'] = row.title
        mapp['content'] = row.content
        data.append(mapp)

GAE - Template

GAE - Introduction

Introduction

Google App Engine is the platform for building web application. There's a built-in framework and already hosting servince provided by Google. The application environtment is two: Java and Python. Whenever you choose one, it's up to you.

How To

To starting development, you can download it first from code.google.com. Here we use Python version environment. After finishing for downloading, please install it.

The first is create directory, named "Hello" in whatever you want to place it - for example in "D:\\Hello". The second, is create two files: app.yaml and main.py, and then write this code.

GAE - Introduction

JS -- AJAX

Introduction

AJAX is a mechenisme for communicating with server through background. It enables your client web site to load and sending data from and to server respectively without reloading the page.

Sending Data To Server

Here's a simple example on how to use ajax.

Program Code: Client Side

<input type="text" id="name"/>
<input type="button" value="Send" onclick="sending()"/>

<script>

function sending(){

  var name = document.getElementById('name').value;
  var ajax = new XMLHttpRequest();
  ajax.open("GET", "hello.php?name="+name, false);
  ajax.send();

}

</script>

It's not so complicated. The fisrt, you have the data. The second, you declare an object instance of ajax throught XMLHttpRequest. Then you send your data through ajax. Finish.
And on the server side, you need to write the code to handle it. Here's a code on PHP.

Program Code: hello.php

$name = $_GET['name'];

From the above code, you see that you handling the data as it comes from common request.

JS -- AJAX

JS - JSON

Introduction

JSON is a data format for transferring data as an alternative to XML. JSON is ligter than XML. The syntax is like mapping.

Program Code

var data = {
  "name": "Lady Gaga",
  "city": "New York",
  "age": 24
}

In the above example, we have JSON data format.

JS - JSON

Python - File Reading And Writing

Introduction

File operation is necessary in every programming.In Python, file handling is comparatively easier than the other language.

Reading A File

For reading a file, you can use open built-in method with or without "r" mode as a second arguments.

Program Code

finput = open("lola.txt")
print finput
data = finput.read()
print data

Output

<open file 'none.txt', mode 'r' at 0x00B34440>
Welcome to Python world. Python is a nice language. It's fun to learn. And it's easy to use.

In the above code, we open file accesss using open built in method and supply its argument with filename. Then we use read method to read all the contents of the file, and save it in variable data.

Python - File Reading And Writing

Python - Dictionary

Introduction

Python dictionary data structure is like a map in another language like java or associative array in php. It's use a name value pairs.

How To

You use bracket for declaring and defining it. Here's a code.

Program Code

data = {"name":"lady gaga", "city":"new york", "age":24}
print data

Output

{"name":"lady gaga", "city":"new york", "age":24}

Python - Dictionary

Python - Tuple

Introduction

Tuple is like a list. That is it's a container of data. It also can contain different type of data. But the difference of tupple and list is that the tuple data cannot be modified after it's defined. You cannot modify or delete an element in the tuple. There's some data structure that suitable used tuple than list. For example the day names in a week, the month names in a year, the songs of lady gaga monster ball album. The different things a gain for tuple than list is that tuple definition is using ( and ). Other is same as list.

Program Code

days = ("sunday", "monday", "tuesday", "wednesday", "thursday", "friday", "saturday")
print days
print "The length of the days: ", len(days)

Python - Tuple

Python - List

Introduction

List is a data structure in Python. It's like an array in other programming languages. But list in Python is more powerful, because it can contain different data type.

Program Code

name = ["lady gaga", "luna maya", "aura kasih"]
print name

Output

["lady gaga", "luna maya", "aura kasih"]

Python - List

C - Define

#define MODULE_AUTHOR(auth) printf("Author: %s\n",auth)
#define MODULE_DESCRIPTION(desc) printf("Description: %s\n", desc)

MODULE_AUTHOR("Irfanudin Ridho");
MODULE_DESCRIPTION("File System");

C - Define

C - String Memory Handling

1. memcpy

char name[] = "lady gaga and barack obama";

char data[100];

memcpy(data, name, strlen(name)+1);

puts(data);

2. memset

char name[] = "lady gaga";

memset(name, '*', 5);

puts(name);

3. memmove

char name[] = "lady gaga and luna maya";

memmove(name+0, name+5, 4); // placed, starting, num

puts(name);

C - String Memory Handling

C - Iterate Pointer Of Char

To iterate a pointer of char, it's just need like doing with custom looping

char *data = "lady gaga";

for(; *data!='\0'; data++){

    putchar(*data);

}

Or using this one:

while(*data != '\0'){
    putchar(*data);
    data++;
}

C - Iterate Pointer Of Char

C - Malloc And Calloc

When we use malloc? We use it when we have a pointer, and we want to initialize it.

char name[] = "lady gaga";

char *ptr;

ptr = (char*) malloc(sizeof(name) * sizeof(char))

And then it's okey to initialize it through assignment or strcpy

ptr = name;

or 

strcpy(ptr, name);

Calloc is same as malloc:

ptr = (char*) calloc(sizeof(name), sizeof(char))

When you need copy an array of char to an array of char, the one way is use strcpy function

char name[] = "Indonesia";

char data[100];

strcpy(data, name);

C - Malloc And Calloc

Python - Class and Static Methods

class Advanced(object):
    def __init__(self, name):
        self.name = name
    def Description():
        return 'This is an advanced class.'
    def ClassDescription(cls):
        return 'This is advanced class: %s' % repr(cls)
    Description = staticmethod(Description)
    ClassDescription = classmethod(ClassDescription)

obj1 = Advanced('Nectarine')
print obj1.Description()
print obj1.ClassDescription()
print '=' * 30
print Advanced.Description()
print  Advanced.ClassDescription()

This is an advanced class.
This is advanced class: <class __main__.Advanced at 0x401c926c>
==============================
This is an advanced class.
This is advanced class: <class __main__.Advanced at 0x401c926c>

Python - Class and Static Methods

Python - Static Data

>> class One:

...    age = 45

...    def inc(self):

...        One.age = One.age + 1

...    def get(self):

...        return One.age

...

>> a = One()

>> b = One()

>> a.inc()

>> b.get()

>> a.inc()

>> b.get()

Python - Static Data

Python - Pipe

>> import os

>> cmd = "dir"

>> fp = popen(cmd)

>> print fp.read()
>> fp.close()

Python - Pipe

Python - anydbm Module

>> import anydbm

>> db = anydbm.open("data.db","c")

>> db["lady"] = "Gaga"

>> db["luna"] = "Maya"

>> print db["lady"]

Python - anydbm Module

Mics - ub IP List

('dudde.ub.ac.id', '175.45.184.100')
('DI-PPTI', '175.45.184.101')
('mail.ub.ac.id', '175.45.184.111')
('simpeg.ub.ac.id', '175.45.184.116')
('hostingdosen.ub.ac.id', '175.45.184.118')
('external-gw.ub.ac.id', '175.45.184.129')
('internal-gw.ub.ac.id', '175.45.184.130')
('dmz-gw.ub.ac.id', '175.45.184.131')
('collo-gw.ub.ac.id', '175.45.184.132')
('inherent-gw.ub.ac.id', '175.45.184.138')
('proxy.ub.ac.id', '175.45.184.162')
('radius.ub.ac.id', '175.45.184.163')
('ns1.ub.ac.id', '175.45.184.164')
('ns2.ub.ac.id', '175.45.184.165')
('central-sw.ub.ac.id', '175.45.184.167')
('proxy2.ub.ac.id', '175.45.184.168')
('ldap.ub.ac.id', '175.45.184.170')
('lpse.ub.ac.id', '175.45.184.51')
('lpse-lat.ub.ac.id', '175.45.184.52')
('smtp-lpse.ub.ac.id', '175.45.184.55')
('simak-db.ub.ac.id', '175.45.184.57')
('siam-sv1.ub.ac.id', '175.45.184.58')
('esxi4.ub.ac.id', '175.45.184.59')
('blog.ub.ac.id', '175.45.184.60')
('devel-gw.ub.ac.id', '175.45.184.66')
('bais.ub.ac.id', '175.45.184.67')
('netmon.ub.ac.id', '175.45.184.68')
('www.ub.ac.id', '175.45.184.70')
('mail.ub.ac.id', '175.45.184.71')
('students-mail.ub.ac.id', '175.45.184.72')
('ftp.ub.ac.id', '175.45.184.73')
('ws.ub.ac.id', '175.45.184.75')
('siakad.ub.ac.id', '175.45.184.76')
('bridgedb.ub.ac.id', '175.45.184.77')
('siakad-db.ub.ac.id', '175.45.184.78')
('keudb.ub.ac.id', '175.45.184.79')
('sikeu.ub.ac.id', '175.45.184.80')
('smtp-gw.ub.ac.id', '175.45.184.81')
('lists.ub.ac.id', '175.45.184.82')
('inherent.ub.ac.id', '175.45.184.83')
('lecture.ub.ac.id', '175.45.184.85')
('siam.ub.ac.id', '175.45.184.86')
('hosting2.ub.ac.id', '175.45.184.87')
('hvm1.ub.ac.id', '175.45.184.89')
('selma.ub.ac.id', '175.45.184.90')
('hosting.ub.ac.id', '175.45.184.92')

Mics - ub IP List

C++ - Building Manipulator

ostream &sep(ostream &stream){
    stream << '\t';
    return stream;
}

C++ - Building Manipulator

C++ - Manipulaltion Output

    cout << "Table" << endl;
    cout << setw(15) << setiosflags(ios::left) << "Name";
    cout << setw(15) << setiosflags(ios::left) << "City";
    cout << setw(10) << setiosflags(ios::left) << "Age" << endl;

    string names[] = {"lady gaga","luna maya","aura kasih","barack obama"};
    string cities[] = {"new york","denpasar","jakarta","white house"};
    int ages[] = {24, 27, 25, 50};
    cout << "===================================" << endl;
    for(int i=0;i<4;i++){
        cout << setw(15) << setiosflags(ios::left) << names[i];
        cout << setw(15) << setiosflags(ios::left) << cities[i];
        cout << setw(10) << setiosflags(ios::left) << ages[i] << endl;
    }

C++ - Manipulaltion Output

Python - Build Web Client

This is a small code for emulating on how to a web client connect to server:

file: client.py
import socket

HOST = 'localhost'
PORT = 6003
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect((HOST, PORT))

# request line
http_data = 'GET /index.php HTTP/1.1\n'

# header line - all are optional but Host
http_data = http_data + 'Host: localhost:80\n'  # required
http_data = http_data + 'From: irfan.ub@gmail.com\n'
http_data = http_data + 'User-Agent: Lucia Browser\n'
http_data = http_data + 'Keep-Alive: 10\n'
http_data = http_data + 'Accept: text/html\n'
http_data = http_data + 'Connection: close\n'

# separation line - required
http_data = http_data + '\n'    # required

client.send(http_data)

data = client.recv(1024*5)
client.close()
print 'Received\n=================\n', data

The response header is like this:
Received
=================
HTTP/1.1 200 OK
Date: Sun, 01 May 2011 22:19:28 GMT
Server: Apache/2.2.14 (Win32) DAV/2 mod_ssl/2.2.14 OpenSSL/0.9.8l mod_autoindex_
color PHP/5.3.1 mod_apreq2-20090110/2.7.1 mod_perl/2.0.4 Perl/v5.10.1
X-Powered-By: PHP/5.3.1
Set-Cookie: PHPSESSID=ajunliavga128hlvcou4chigv6; path=/
Expires: Thu, 19 Nov 1981 08:52:00 GMT
Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Pragma: no-cache
Content-Length: 114
Connection: close
Content-Type: text/html

<form action="test.php" method="post">
<input type="text" name="text"/> Holla</form>
<a href="test.php">Test</a>

Python - Build Web Client

Python - Bulding Web Server

Here's a short code on how to build workable web server:

name: server.py

import socket

HOST = ''
PORT = 6003

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((HOST, PORT))
server.listen(2)
conn, addr = server.accept()

print 'Connected by', addr

# initial lines
data = 'HTTP/1.0 404 Not Found\n'

# header lines - all are optional
data = data + 'Date: Fri, 31 Dec 2011 10:12:13 GMT\n'
data = data + 'Content-Type: text/html\n'
data = data + 'Content-Length: 22\n'
data = data + 'Server: Lucia Web Server\n'

# separating lines. needed
data = data + '\n'

# body
data = data + '<html><head><title>Hello World</title></head><body>'
data = data + '<h1>hello World</h1></body></html>'

# receiving the request headers from browser
datas = conn.recv(1024)
print datas


# send the response header plus the body
conn.send(data)
conn.close()



These the request header of the browser:

GET /index.html HTTP/1.1
Host: localhost:6003
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.17) Gecko/2
0110420 SVD Firefox/3.6.17
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive


Accessed from telnet
>>telnet
telnet>> open localhost 6003 HTTP/1.0 /index.hmtl

Python - Bulding Web Server