Web Artisans: September 2014

How to make own captcha in Joomla?

The captcha can be used in many places to validate whether the user is real or not. It helps in maintaining the security of the site.
The following function will make an image that contains a random captcha in Joomla.

<?php
public function makeCaptcha()
{
$string = JUserHelper::genRandomPassword ('6');
$session = JFactory::getSession();
$session->set('value', $string);
$width = 100;
$height = 25;
$image = imagecreatetruecolor ($width , $height);
$text_color = imagecolorallocate($image, 130, 130, 130);
$bg_color = imagecolorallocate($image, 190, 190, 190);
imagefilledrectangle($image, 0, 0, $width, $height, $bg_color);
imagestring($image, 5, 16, 4, $string, $text_color);
ob_start();
imagejpeg ($image);
$jpg = ob_get_clean ();
return "data:image/jpeg;base64," . base64_encode($jpg);
}
?>

How to Compile a C Program on Ubuntu

This article will guide you to compile a C program on Ubuntu using the GNU gcc/g++ compiler. Additions were made in order to simplify and clarify the creation of a C program on Ubuntu.

1. Open up a terminal on Ubuntu and install the build-essential package by typing the following command in the terminal

sudo apt-get install build-essential
This will install the necessary C development libraries for your Ubuntu system to create C programs.

2. Create a directory and a sub directory to hold your C programs and your main HelloWorld program.

mkdir -p CProgram/HelloWorld
We are using CProgram for the main directory to hold our created C programs and we are using the sub directory HelloWorld to hold our main program.

3. Then we will change into our created directory by issuing the following command

cd CProgram/HelloWorld

4. Next we will use a text editor such as gedit or nano to create our C or C++ source code using the following command.

gedit main.c

nano main.c

5. Enter the source code of your program. For example: the HelloWorld program is as follows:

#include<stdio.h>
#include<stdlib.h>
int main()
{
printf("Hello World,\nThis is my first program compiled on Ubuntu.");

return 0;
}

6. Save the file as main.c and exit.

7. Compiling your C program

Make sure you are in the CProgram/HelloWorld directory before you compile your C programs.

Now type in the terminal:

gcc -Wall -W -Werror main.c -o HelloWorldC
The first line will invoke the GNU C compiler to compile the file main.c and output (-o) it to an executable called HelloWorldC.
The options -Wall -W and -Werror instruct the compiler to check for warnings.

9. If you get the permission errors, you need to make the file executable. You can do this by issuing the following commands below

chmod +x HelloWorldC

10. In order to execute your program you will have to type in the following commands.

./HelloWorldC

[Note: All the sentences that are highlighted are the commands that have to be written in Ubuntu terminal.]

Hack Facebook Using BiNu App on Mobile.

Follow following Steps to hack a Facebook account:

At first, download biNu app on mobile phone. Click HERE to download. (Currently biNu is not supported on the iPhone & Windows Phone)
After finishing the download just install it (automatically installs in android).
After that, Create a biNu's Account.
Now visit biNu's homepage and you will see Facebook icon.
Just click it you see Login screen of Facebook. It opens in the default browser of your phone.
Don't Login into Facebook.
Just copy the link from the address bar of your browser. (For example, the link should be like this: http://m.facebook.com/login.php?app_id=378628085054&skip_api_login=1&cancel=http%3A%2F%2Fm.binu.com%2Ffclient%2Fauth.php%3Ferror_reason%3Duser_denied%26error%3Daccess_denied%26error_description%3DThe%2Buser%2Bdenied%2Byour%2Brequest.%26state%3D335074%257C46567955%257C36.252.21.228&fbconnect=1&next=https%3A%2F%2Fm.facebook.com%2Fdialog%2Fpermissions.request%3F_path%3Dpermissions.request%26app_id%3D378628085054%26client_id%3D378628085054%26redirect_uri%3Dhttp%253A%252F%252Fm.binu.com%252Ffclient%252Fauth.php%26display%3Dtouch%26response_type%3Dcode%26state%3D335074%257C46567955%257C36.252.21.228%26perms%3Duser_about_me%252Cfriends_about_me%252Cuser_status%252Cfriends_status%252Cread_friendlists%252Cread_stream%252Cread_mailbox%252Coffline_access%252Cpublish_stream%252Cxmpp_login%26fbconnect%3D1%26from_login%3D1&rcount=1&_rdr)
After this visit https://bitly.com/ or https://goo.gl/ on your computer browser or mobile browser and get short link. (For example, the link should be like this: http://goo.gl/9HJCHa)
Now send this short link to your friend (the victim) one at a time.
After sending link to victim, refresh the Facebook at biNu's homepage. At this point the victim should have clicked on that link.
Now enjoy. You can read messages, post on wall, see friends list, update status and many more.

HAPPY HACKING. Do comment if you like.

How to find second greatest number in an array?

Source Code:

//second greates among array

#include<iostream>

using namespace std;

int great (int a[],int n)

{

int i,greatest;

greatest=a[0];

for (i=0;i<n;i++)

{

if(a[i]>greatest)

greatest=a[i];

}

return greatest;

}

int second (int a[],int n)

{

int i,second,g;

g=great(a,n);

if(a[0]==g)

second=a[1];

else

second=a[0];

for(i=0;i<n;i++)

{

if(a[i]>second&&a[i]<g)

{

second=a[i];

}

return second;

}

int main()

{

int n,a[40],j;

cout<<"How many numbers? ";

cin>>n;

cout<<"Enter "<<n<<" numbers\n";

for(j=0;j<n;j++)

cin>>a[j];

cout<<"The greatest number is "<<great(a,n)<<endl;

cout<<"The second greatest number is "<<second(a,n)<<endl;

system("pause");

return 0;

}

Output:

Insertion Sort in C++

Source Code:

//insertion sort
#include<iostream>
#include<stdlib.h>
using namespace std;
class insertion
{
private:
int n,key;
int stack[100],temp;
public:
void getinput()
{
cout<<"How many nuumbers in array? ";
cin>>n;
cout<<"Enter "<<n<<" numbers: ";
for (int i=0;i<n;i++)
cin>>stack[i];
}
void ascending()
{
for (int i=1;i<n;i++)
{
while(i>0 && stack[i]<stack[i-1])
{
temp=stack[i];
stack[i]=stack[i-1];
stack[i-1]=temp;
i--;
}
}
}
void descending()
{
for (int i=1;i<n;i++)
{
while(i>0&&stack[i]>stack[i-1])
{
temp=stack[i];
stack[i]=stack[i-1];
stack[i-1]=temp;
i--;
}
}
}
void showoutput()
{
cout<<"\nThe sorted numbers are: ";
for(int j=0;j<n;j++)
cout<<stack[j]<<"\t";
cout<<"\n----------------------------------------------- --------------\n";
}
};
int main()
{
insertion q;
int choice;
cout<<"\n**************************\n******INSERTION SORT******\n**************************\n";
while (1)
{
cout<<"\n1-> Sort in ascending order\n";
cout<<"2-> Sort in descending order\n";
cout<<"3-> Exit\n";
cout<<"\n\nEnter your choice(1, 2 or 3): ";
cin>>choice;
switch(choice)
{
case(1):
q.getinput();
q.ascending();
q.showoutput();
break;
case(2):
q.getinput();
q.descending();
q.showoutput();
break;
case(3):
exit(1);
}
}
system("pause");
return 0;
}

Output:

How to find waiting time in a single server queue system?

Source Code:

//single server queuing system
#include<iostream>
#include<conio.h>
using namespace std;
int main()
{
int n, i, a[10], s[10], w[10];
float wa=0.0;
cout<<"\n***SINGLE SERVER QUEUING SYSTEM***"<<endl;
cout<<"Get Ready!!! You are in!!!"<<endl;
cout<<"\nPress any key to run..."<<endl;
getch();
cout<<endl;
cout<<"Enter the number of customers: ";
cin>>n;
cout<<"Enter the arrival times of "<<n<<" customers: ";
for(i=1; i<=n; i++)
cin>>a[i];
cout<<"Enter the service times of "<<n<<" customers: ";
for(i=1; i<=n; i++)
cin>>s[i];
cout<<endl<<"\t--------------------------------------------- --------------"<<endl;
cout<<"\t|Customer id | Arrival Time | Service Time | Waiting Time |"<<endl;
cout<<"\t--------------------------------------------------- --------"<<endl;
w[1]=0;
for(i=1; i<=n; i++)
{
w[i+1]=w[i]+s[i]-a[i+1];
cout<<"\t|\t"<<i<<" |\t "<<a[i]<<"\t |\t" <<s[i]<<"\t |\t"<<w[i]<<"\t |"<<endl;
wa+=w[i];
}
cout<<"\t--------------------------------------------------- --------"<<endl<<endl;
cout<<"Average waiting time = " <<wa/n<<endl<<endl<<endl<<endl;
system("pause");
return 0;
}

Output: