Computer Programming Interests

Inkscape - How to draw a rectangle with round corners

2010-03-13T07:13:00.000-08:00

Hello,

In this period I'm studying Inkscape drawing and I want to show you how to draw a simple rectangle with round corners:
a) select rectangle tool on the left.
b) a change bar will appear:
*set Rx and Ry to 16 to have round corners on the rectangle you will draw.
*set Rx and Ry to 0 to go back to normal rectangle.

That's all.

Eclipse identification FAIL

2009-11-19T06:11:00.001-08:00

Eclipse identification FAIL

at here:

Paul.

Eclipse

2009-11-19T06:08:00.000-08:00

Hello everybody.
Right now I'm learning JSF.
And while working with internationalization and localization and resource bundle I got this nice error:

Paul.

Combining JSP JavaBeans Servlets

2009-10-17T01:45:00.000-07:00

Hello everyone,

I haven't wrote on this blog for a long, long time.
I actually was busy with finishing the computer science faculty.
Now I'm at master studies in computer science.

One of the first challanges was Java Web Technologies(using J2EE).
JSP, JavaBeans, Servlets.
A Web application can be wrote as a MVC.
Control-Servlet
JSP-View
JavaBeans-Model.

The comunication between JSP and Servlets is made using JavaBeans:
a) A JavaBeans is a public class that:
The required conventions are:
*The class must have a public default constructor. This allows easy instantiation within editing and activation frameworks.
*The class properties must be accessible using get, set, and other methods (so-called accessor methods and mutator methods), following a standard naming convention. This allows easy automated inspection and updating of bean state within frameworks, many of which include custom editors for various types of properties.
*The class should be serializable. This allows applications and frameworks to reliably save, store, and restore the bean's state in a fashion that is independent of the VM and platform.

//example:
/**
* Class PersonBean.
*/
public class PersonBean implements java.io.Serializable {

private String name;

private boolean deceased;

/** No-arg constructor (takes no arguments). */
public PersonBean() {
}

/**
* Property name (note capitalization) readable/writable.
*/
public String getName() {
return this.name;
}

/**
* Setter for property name.
* @param name
*/
public void setName(final String name) {
this.name = name;
}

/**
* Getter for property "deceased"
* Different syntax for a boolean field (is vs. get)
*/
public boolean isDeceased() {
return this.deceased;
}

/**
* Setter for property deceased.
* @param deceased
*/
public void setDeceased(final boolean deceased) {
this.deceased = deceased;
}
}

b)a JSP page using a JavaBean:
<% // Use of PersonBean in a JSP. %>

Name:

Deceased?

c)The Servlet-I will only list the part necessary to take the bean and use it:
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
HttpSession session=request.getSession();
PersonBean pers=(PersonBean)session.getAttribute("person");
out.print(pres.getName());

//we also can set and send a bean
session.setAttribute("person2", pers);
getServletContext().getRequestDispatcher("Result.jsp").forward(request, response);
}

Paul.

Tools for my Selenium tests

2008-07-27T13:14:00.000-07:00

Here are my tools:

Windows XP,Vista & Ubuntu 8.04
Eclipse(I forgot to mention that I write my tests in java): with Subversion plugin&Maven plugin.
Maven tool installed as standalone with .m2 repository directory.
Mozilla Firefox(2&3 - you will understand why later):
-with next plugins and addons:
*Selenium IDE - will help a lot;
*Firebug - If you have Ajax code with Source View of Mozilla you will not see the source and firebug is here to save us;
*XPath Checker for short XPath to that element;
*XPather Browser for the long XPath to element.

Paul.

Selenium tests for Summer.

2008-07-25T02:15:00.000-07:00

This summer I'm gone write selenium tests for a web application: XWIKI.
So this summer I'll learn you about selenium tests.

Paul.

P.S.: Sorry about java posts that I've promised. I promise that I will tell you more about it later when I will learn how to write a web application with java technologies.

More about iterators

2008-05-04T13:46:00.000-07:00

Iterators(C++) can be definied for object of classes from std.
Examples: vector, list, map, etc.

Example for vector:
//header
#include vector

//type definition
typedef vector vect;
//type declaration
vect v(20);

//iterator definition
typedef vect::iterator vectiter;
//iterator declaration
vectiter v;

//iterator use
//listing all the values in vector
for(vectiter i=vect.begin() ; i!=vect.end() ; ++i ){
//two ways:
cout<< i->list();
cout<<(*i).list();
}

//other iterator use
//deleting a value from vector
vectiter i=vect.find(new int(5));
if(i==vect.end())
{
cout<<"The element doesn't exist";
}
else{
vect.erase(i);
}

A lex example for Simple language

2008-04-29T23:26:00.000-07:00

Simple language looks like this:
LET
declarations of variables.
IN
statements;
END

declarations of variables:
INTEGER i.

statements:
READ i;

the lex example that generates a lexical analyzer:
ident [a-z][a-zA-Z0-9]*
digit [0-9]
number [0-9][0-9]*
%%
"LET"|"IN"|"END"|"INTEGER"|"READ"|"WRITE" { printf("Key word: %s",yytext); }
("INTEGER")(" ")+({ident})(" ")* { printf("Token variable declaration: %d",yytext); }
("READ")(" ")*({ident})(" ")*(";") { printf("Token : %s",yytext); }
("WRITE")(" ")*({ident})(" ")*(";") { printf("Token : %s",yytext); }
%%
main(char *argv[])
{
yyin=fopen(argv[1],"r");
yyout=fopen(argv[2],"w");
}

A regular expression for lex

2008-04-29T23:13:00.000-07:00

Now I'm real busy, but I will still write about lex.
A regular expression is used for identification of patterns in a text.
There are some rules:
* - it means that the block that has this at the end can appear 0 times or many times;
+ - it means that the block that has this at the end can appear 1 times or many times;
? - it means that the block that has this at the end can appear 0 time or 1 time;

Example:
//this is a lex example
("for")(" ")*("(")(";")(";")(")")(" ")*("(")

this regular expression is for:
for(;;){
or
for (;;) {

I've put the (" ")* because there can be as many spaces as 0 or many.

About lex

2008-03-17T13:16:00.000-07:00

Lex is tool that is generating lexical analyzers.
It generally works with regular expressions.
Having a set of rules.

Main structure:
Definition section
%%
Rules section
%%
C/C++/Java code section

This tool is implemented for the common know programming languages:
- C/C++ -PCLex,Flex
- Java - JLex.

Addresses were you can download lex:
http://www.cs.princeton.edu/~appel/modern/java/JLex/(for JLex)
http://flex.sourceforge.net/ (Flex).

I haven't wrote for a while

2008-03-17T13:08:00.000-07:00

Being a little busy I forgot about the blog.

The next posts I've been thinking are:
-Lex: who to use it(4-6 posts).
-Java Interface - How to send a method as parameter(2 posts).

I'll see what will be next.

Paul.

RSA with NTL(in english)

2008-02-15T07:47:00.001-08:00

#include <ntl/zz.h>
NTL_CLIENT

ZZ power2(ZZ m,ZZ pow,ZZ n){
ZZ i,m2;
i=1;m2=1;
while(i<=pow){
m2=(m2*m)%n;
i++;
}
return m2;
};

int main(void){
ZZ p,q,d,e,n,fi,msg,cr,dr;

cout<<"Reading p and q:";
cin>>p;
cin>>q;
n=p*q;
fi=(p-1)*(q-1);
cout<<"n:"<<n<<":fi:"<<fi<<endl;
cout<<"Reading message(numbers):";
cin>>msg;
cout<<"Reading d:";
cin>>d;
cout<<"Inverse modulare:";
e=InvMod(d, fi);
cout<<e<<endl;
cout<<"Cryptotext:";
cr=PowerMod(msg,e,n);
cout<<cr<<endl;
cout<<"DeCrypted:";
dr=PowerMod(cr,d,n);
cout<<dr<<endl;

ZZ x,yq,yp,dq,dp,i,c1,c2,x1,x2;
dq=d%(q-1);
dp=d%(p-1);
i=1;yp=1;
while(i<=dp){
yp*=cr;
yp%=p;
i++;
}
i=1;yq=1;
while(i<=dq){
yq*=cr;
yq%=q;
i++;
}

c1=q%p;
c2=p%q;

int i2,j2;
i2=0;j2=0;
while(c1*i2-yp!=j2*p){
if(j2<p) j2++;
else {j2=0; i2++;}
}
x1=i2;
i2=0;j2=0;
while(c2*i2-yq!=j2*q){
if(j2<q) j2++;
else {j2=0; i2++;}
}
x2=i2;

x=(x1*q+p*x2)%(q*p);
cout<<"Decrypted cu TCR:"<<x<<endl;
return 0;
}

Result for RSA(with small numbers)

2008-02-15T07:40:00.000-08:00

For:
p=1511
q=1409
d=17

x=1704

n=2128999
fi=2126080
e=1875953

Cryptotext=219017
Decrypted=1704

RSA with NTL

2008-02-15T07:29:00.001-08:00

#include <ntl/zz.h>
NTL_CLIENT

ZZ power2(ZZ m,ZZ pow,ZZ n){
ZZ i,m2;
i=1;m2=1;
while(i<=pow){
m2=(m2*m)%n;
i++;
}
return m2;
};

int main(void){
ZZ p,q,d,e,n,fi,msg,cr,dr;

cout<<"Citire p si q:";
cin>>p;
cin>>q;
n=p*q;
fi=(p-1)*(q-1);
cout<<"n:"<<n<<":fi:"<<fi<<endl;
cout<<"Citire mesaj:";
cin>>msg;
cout<<"Citire d:";
cin>>d;
cout<<"Invers modular:";
e=InvMod(d, fi);
cout<<e<<endl;
cout<<"Criptat:";
cr=PowerMod(msg,e,n);
cout<<cr<<endl;
cout<<"DeCriptat:";
dr=PowerMod(cr,d,n);
cout<<dr<<endl;

ZZ x,yq,yp,dq,dp,i,c1,c2,x1,x2;
dq=d%(q-1);
dp=d%(p-1);
i=1;yp=1;
while(i<=dp){
yp*=cr;
yp%=p;
i++;
}
i=1;yq=1;
while(i<=dq){
yq*=cr;
yq%=q;
i++;
}

c1=q%p;
c2=p%q;

int i2,j2;
i2=0;j2=0;
while(c1*i2-yp!=j2*p){
if(j2<p) j2++;
else {j2=0; i2++;}
}
x1=i2;
i2=0;j2=0;
while(c2*i2-yq!=j2*q){
if(j2<<q) j2++;
else {j2=0; i2++;}
}
x2=i2;

x=(x1*q+p*x2)%(q*p);
cout<<"Decriptare cu TCR:"<<x<<endl;
return 0;
}

NTL functions

2008-02-11T07:18:00.000-08:00

//to generate Inverse Modular for a number
e=InvMod(d,fi)

//to raise a number at a power
y=PowerMod(x,n)

//to generate prime numbers
GenPrime().

More about programming interests and examples:
http://www.shoup.net/ntl/doc/tour-struct.html
http://www.shoup.net/ntl/doc/tour-examples.html

RSA cryptosystem.

2008-02-11T06:57:00.000-08:00

We will work a small example with NTL. And that will be RSA cryptosystem.

RSA is a cryptosystem with public-private key:
-public key (n,e);
-private key (p,q,d,fi).

p,q are large prime numbers(we generate them).
we also choose d.

n=p*q;
fi=(p-1)*(q-1);
e=InvMod(d,fi);
(e*d)%fi=1.

x-message.
y-crypted message.
y=(x at power e)%n.
x1-decrypted message.
x1=(y at power d)%n.

How to use NTL

2008-02-03T05:40:00.000-08:00

Now that we compile one version of NTL(later I will show for the rest of the versions) let's see how we can use it.

We will still use Visual C++ 6.0 and the compiled file ntl.lib.

Let's begin.

Step 1:
Create a new project.
Named it and choose Win32 Console Application.

Step 2:
Add to the project the file ntl.lib(Project -> Add -> Files).

Step 3:
We also have to include to the project the \\include directory.
The same way as we did when we compiled the ntl library.
Project ->Settings -> C/C++
Category:Preprocessor.
Additional include directories: c:\\ntl\\WinNTL-yyy\\include.

Step 4:
When we like to work with ntl functions we have to write this lines of code:

#include <NTL/ZZ.h>
NTL_CLIENT.

Paul.

How to compile NTL

2008-02-03T05:16:00.000-08:00

I've been a bit busy with school exams, so I didn't wrote on the blog.

First compilation will be for Visual Studio 6.0 versions 5.1 to 5.3.2 of NTL.
Save the files in c:\\ntl(you can save it anywhere else only to know exactly).

Step 1:
Make a new project(File->New-Project)
give it the name you like and choose the project type: Win 32 static library. In rest leave the settings as they are.

Step 2:
Add the NTL files to the project(Project -> Add to Project -> Files).
Files are at c:\\ntl\\WinNTL-yyy\\src.

Step 3:
Important step because now we will include the headers files.
Project ->Settings -> C/C++
Category:Preprocessor.
Additional include directories: c:\\ntl\\WinNTL-yyy\\include.

Now build.

The result is a file: ntl.lib.

A version of this compilation can be found here:
http://students.info.uaic.ro/~paul.guralivu/ntl3_2.lib

Paul.

More about NTL

2008-01-21T07:38:00.000-08:00

To keep informations safe you have to use efficent crypting algorithms.Nowadays anybody can break ancient cryptosystem in 10 min with an usual pc. It's been proven that you have to work with big numbers(for dss you need a number between 2 at the power 512 and 2 at the power 1024). With a simple pc this are numbers that can't be counted, because the computers
doesn't have the structure for it.

So somebody decide to write a library about it.
Called NTL - A Library for doing Number Theory.

In this tutorial I'll show you how to compile it and use it.

You can find more about it at:
http://www.shoup.net/ntl/

Next time

2008-01-17T07:29:00.000-08:00

I will come back at servers later.

I will post some servers-clients that I wrote.

Next time I will post about NTL library used in cryptography for big numbers.
This isn't the only domain in which is used. There are many others.

And I will post rsa public-key cryptosystem in C with NTL.

Our first server

2008-01-17T07:14:00.000-08:00

//the server will only support to clients with will send messages one to the other
//and we will make 1 son for the second client

//we include the same libraries with the same functions
//just 2 more sys/socket.h and sys/types.h
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <netdb.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <signal.h>
#include <errno.h>
extern int errno;

//we declare int argc and char *argv[], because we will give the port on the command line
int main(int argc,char *argv[]){
int i,sk,walking[20],ct,pid[2],m,l;
struct sockaddr_in st1,st2;
char buf[1000],buf2[1000]={"Client1:"},buf3[1000]={"Client2:"};

//we create the socket
if((sk=socket(PF_INET,SOCK_STREAM,0))==-1){
perror("Eroare la socket.");
exit(1);
}

//we create the structure with the parameters for the server
//with parameters like port,types of address accepted
st1.sin_addr.s_addr=htonl(INADDR_ANY);
st1.sin_family=AF_INET;
st1.sin_port=htons(atoi(argv[1]));

//we open the server to connections
if(bind(sk,(struct sockaddr*)&st1,sizeof(st1))==-1){
perror("Eroare la bind.");
exit(1);
}

if(listen(sk,5)==-1){
perror("Eroare la LISTEN.");
exit(1);
}

//accepting the first client
if((walking[0]=accept(sk,NULL,NULL))==-1){
perror("Eroare la accept.");
exit(1);
}
//we accept the second client
walking[1]=accept(sk,NULL,NULL);
pid[0]=fork();
if(pid[0]==0){
bzero(buf,1000);
//the first client reads what the second sent to him
while(read(walking[0],buf,sizeof(buf))>0){
for(m=0,l=10;m<(int)strlen(buf);m++,l++) buf2[l]=buf[m];
write(walking[1],buf2,sizeof(buf)); } } pid[1]=fork(); if(pid[1]==0){ bzero(buf,1000);
//the second client reads what the first send him
while(read(walking[1],buf,sizeof(buf))>0){
for(m=0,l=10;m<(int)strlen(buf);m++,l++)
buf3[l]=buf[m];
//sending the message to the first client
write(walking[0],buf3,sizeof(buf));
}
}

close(sk);
return 0;
}

A few structs that we will use

2008-01-13T11:33:00.000-08:00

//there are 2 important structs that are used in day-to-day programming
struct sockaddr{
uint8_t sa_len;
sa_family_t sa_family;
char sa_data[14];
};
//but the structure we will really use is
struct sockaddr_in{
uint8_t sin_len;
sa_family_t sin_family; //specify the socket family:AF_INET,AF_ROUTE,AF_UNIX
in_port_t sin_port;//specify the port(e.g. 80 for HTTP see the posts about ports)
struct in_addr sin_addr; //here should be the type of addresses allowed to connect the server
//to allow all of them we will use INADDR_ANY
char sin_zero[8];
};
//and a structure used in tcp clients which is filled when function
//gethostbyname is called
struct hostent{


     char *h_name; //server name

char **h_aliases; //server aliases

int h_addrtype;

int h_length;

char **h_addr_list;//very important here are the ip addresses

char *h_addr;//the first ip address
};

More about functions used in a server programming

2008-01-13T07:55:00.000-08:00

here are the main functions that we will use:
int socket(int domain, int type, int protocol);
domain=AF_INET,AF_UNIX
type=SOCK_STREAM(for tcp), SOCK_DGRAM(for udp),SOCK_RAW
protocol=0(for transport-we work at a transport level)
-this functions creates a socket
-it returns the descriptor for it if success and different error codes for rest
-types of errors:
EMFILE - Too many open files
ENFILE - Too many open files in system
EACCES - Permission denied
EPROTONOSUPPORT - Protocol family not supported
ENOMEM - Not enough space
ENOBUFFERS - No buffer space available
EINVAL - Invalid argument

int bind(int sockfd,struct sockaddr *myaddr,sizeof(myaddr));
//this function associate an address to an existing socket

int listen(int sockfd,int backlog)
//opens the socket to listen and creates a queue of waiting clients of backlog size(usually 5, but in HTTP clients should be as high as possible)

int accept(int sockfd,struct sockaddr *hostaddr,sizeof(hostaddr))
//with this the server accepts a connection request

//other functions:
read(), write() as used in tcp client

More network libraries

2008-01-13T07:48:00.000-08:00

There will be a number of functions more for the tcp server(concurent).

The libraries are:
//this one is for the structs that we will use in order to make the server run.
#include <sys/types.h>
//this one is for functions needed for a socket.
#include <sys/socket.h>

and been on linux we will use bsd(berkley system distribution) api for network.

Types of servers

2008-01-13T07:23:00.000-08:00

Whether you use UDP or TCP, but take 2 types of servers:
-iterative;
-concurent.

The iterative server support more clients at a time, but is resolving one request at a time. The rest have to wait until their turn will come.
Concurent servers work different: for every client they create on a server a new process/thread in which will treat the request(apache server start with 6 process and add more when new clients are connecting).

The main difference between UDP and TCP servers is that the clients of a UDP server will connect to a port and put their request there, but the TCP clients will use a port just to connect to the server. Once connected they will communicate through the socket.

We will write a tcp server.

About ports

2008-01-07T05:31:00.000-08:00

If I did the mistake I thought why not speak about ports.

network port=logical connection place.
Most of the network protocols got ports for client/server activity.
For ports we have 1 byte allocated(unsigned int).
That means the values are from 0..65536.
But the first 1024 are reserved for services.

Most known:
SNMP - port:161,162
HTTP - port:80
TrivialFTP - port:69
BOOTP - ports:67,68
DNS - port:53
SSH - port:22
TCP,SMTP - port:25
TELNET - port:23
FTP - port:20(date connection),21(control connection)

Next Saturday when I will show how to write a tcp server I will use a port higher than 1024.

Simple TCP Client

2008-01-07T05:14:00.000-08:00

I realized I've made one small problem:
at this line of code I've put 80 for HTTP, but I shouldn't. I should have put the port receive from command line.
serv.sin_port=htons(80);

//corected
//I will use function atoi which will convert string argv[] to a number
serv.sin_port=htons(atoi(argv[2]));

//Simple TCP Client
//put here the libraries from the post of 5 January 2008
extern int errno;
int sk;//socket variable

//we will use a handler to print to screen what we receive from the the server we've connected to
void myhandler(int x){
char buf2[1000];

bzero(buf2,1000);
while(read(sk,buf2,1000)>0){
printf("%s\n",buf2);
}
}

int main(int argc,char *argv[]){
int i;
struct hostent* st1;
struct sockaddr_in serv;

if(argc<2){>");
}
else{
//we create a socket
//it's important to be SOCK_STREAM so we could write to server
//and receive dates
if((sk=socket(PF_INET,SOCK_STREAM,0))==-1){
perror("Err la sk:");
exit(1);
};
//with this function we will get in a structure the ips of server
st1=gethostbyname(argv[1]);
//we asociate our handler to SIGIO signal
//SIGIO is sent everytime a Input/Output operation is made
signal(SIGIO,myhandler);
//binary copy we will copy the first ip from the struct st1_h_addr_list
//and put it into our serv structure
bcopy(st1->h_addr_list[0],&(serv.sin_addr),st1->h_length);
serv.sin_family=AF_INET;
//HTTP port:80
//SSH port:22
//Telnet port:23
//we are interested in HTTP port
serv.sin_port=htons(atoi(argv[2]));

//we are connecting to the server
if((connect(sk,(struct sockaddr*)&serv,sizeof(serv)))==-1){
perror("Err la sk:");
exit(1);
}
else{
//this is the command to get the first page
//char buf[]="GET /index.html HTTP/1.0 \n\n";
char buf[200];

fcntl(sk,F_SETOWN,getpid());
fcntl(sk,F_SETFL,O_ASYNC);

while(1){
fgets(buf,200, stdin);
write(sk,buf,strlen(buf));
}
}
//we have to close the socket
close(sk);
}
return 0;
}

This is all for today

2008-01-05T10:35:00.001-08:00

Maybe next saturday I will speak about
TCP Server(on a high port).

Paul.Wish you all a good weekend.

Different commands that can be posted into a socket to a http server

2008-01-05T10:29:00.000-08:00

example used before was :
GET /index.html HTTP/1.1

GET file.html
HTTP/1.1

there are only 3 version of HTTP(from '89 till now)
0.9 - does not support a lot of things(out of use)
1.0 - one big problem was that everytime you would type something wrong in the opened channel it would closed the connection
and you would have to reconnect(lot of time lost)
1.1 - this is the best

the rest of command you can find in RFC 2616.

Paul.

Here goes the compilations

2008-01-05T10:16:00.000-08:00

//How to compile this program
//if you have a linux under text type
gcc cl.c -o cl
//if cl.c is the name of you source code

//then lunch
./cl
//and a message will apear
cmd host port

//then lunch with paramaters
./cl www.google.com 80

//it should give you the possibility to write something
//if connected

//type
GET /index.html HTTP/1.1

//and you should receive the www.google.com first page in html

Here goes the tcp client

2008-01-05T10:05:00.000-08:00

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <netdb.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <errno.h>
extern int errno;
int sk;//socket variable

//we will use a handler to print to screen what we receive from the the server we've connected to
void myhandler(int x){
char buf2[1000];

bzero(buf2,1000);
while(read(sk,buf2,1000)>0){
printf("%s\n",buf2);
}
}

int main(int argc,char *argv[]){
int i;
struct hostent* st1;
struct sockaddr_in serv;

if(argc<2){> ");
}
else{
//we create a socket
//it's important to be SOCK_STREAM so we could write to server
//and receive dates
if((sk=socket(PF_INET,SOCK_STREAM,0))==-1){
perror("Err la sk:");
exit(1);
};
//with this function we will get in a structure the ips of server
st1=gethostbyname(argv[1]);
//we asociate our handler to SIGIO signal
//SIGIO is sent everytime a Input/Output operation is made
signal(SIGIO,myhandler);
//binary copy we will copy the first ip from the struct st1_h_addr_list
//and put it into our serv structure
bcopy(st1->h_addr_list[0],&(serv.sin_addr),st1->h_length);
serv.sin_family=AF_INET;
//HTTP port:80
//SSH port:22
//Telnet port:23
//we are interested in HTTP port
serv.sin_port=htons(80);

//we are connecting to the server
if((connect(sk,(struct sockaddr*)&serv,sizeof(serv)))==-1){
perror("Err la sk:");
exit(1);
}
else{
//this is the command to get the first page
//char buf[]="GET /index.html HTTP/1.0 \n\n";
char buf[200];

fcntl(sk,F_SETOWN,getpid());
fcntl(sk,F_SETFL,O_ASYNC);

while(1){
fgets(buf,200, stdin);
write(sk,buf,strlen(buf));
}
}
//we have to close the socket
close(sk);
}
return 0;
}

Here goes the functions

2008-01-05T09:49:00.000-08:00

//stdio.h functions
//reading variables
scanf("format",&varb);
format=
"%c"-for char
"%d"-for int
"%f"-for float
"%lf"-for double
"%x"-for hexa
//listing variables
printf("format",varb);
//creating a new process
fork();
//to get the process pid(Process Identifier)
getpid();
//to get the parent process pid(Process Identifier)
getppid();

//stdlib.h functions
//terminating the program
exit(errno);
errno=
0-OK
>1-Errors

//strings.h functions
//returns the numbers of chars in the char []
strlen(char [])
//copies char source in dest
strcpy(char dest[],char source[])
//compares char [] with char []
//if equal returns 0
strcmp(char [],char [])
//concatenate char source to the end of dest
strcat(char dest[],char source[])

//errno.h functions
//work like a printf, but prints the number of errno
perror("Text");

//signal.h functions
//to asociate a function(handler) to a system handler
signal(SIGXXX,functionname);
//to send a signal
kill(process,signal)
//to put your computer to receive a signal
pause();

Here goes the libraries for tcp client

2008-01-05T09:31:00.001-08:00

Libraries needed:
#include <stdio.h>
#include <stdlib.h>
//I will write it in C using Linux API(it should be compiled in Linux - I use Debian - but it will work in other distribution of Linux also - I also compiled in Mandriva 2008).
#include <strings.h>
//we will use some binary(they are in kernel - and they are fast) like bzero(*buffer,size of buffer)
#include <netdb.h>
//needed for socket
#include <string.h>
//for functions like strlen
#include <errno.h>
//we will use perror() function
#include <signal.h>
//we will use some function to treat some signals
#include <fcntl.h>
//will use the fcntl function to make the read function async

extern int errno;
//variable declared in errno.h we will use it for reporting the errno number

Nu am scris de mult

2008-01-05T09:26:00.000-08:00

Nici nu am avut intentia.

Dar m-am gandit ca din moment ce sunt la Facultatea de informatica sa povestesc cate ceva despre lucrurile pe care le facem.

Am sa abordez in luna ce urmeaza:
-Scrierea unui client tcp rudimentar
-Scrierea unui server de smtp
-Compilarea bibliotecii NTL pentru cripto
-Diferite functii din NTL ajutatoare pentru criptografie

Cum arat dupa un an de facultate ?

2007-08-17T05:48:00.000-07:00

Grea intrebare.

La fiecare pas ai de facut alegeri. Alegeri care te maturizea-za. Te schimba. Iti dau aripi sau te arunca la pamant. Alegeri facut voit sau lasat in voi valului.

Nu am nici o "bobita"(restanta pentru novici) si astept cu nerabdare anul II.
Bursa: Nesperata sansa, care totusi am ratat-o la limita in sem. I, nu stiu pe sem. II.

Dumnezeu sa aiba mila de mine!
Al vostru,
ex-boboc,
Paul Guralivu

Dupa 6 saptamani

2006-11-09T03:39:00.000-08:00

Facultatea dupa 6 saptamani...
sunt ingrijorat...
am ramas in urma cu niste cursuri...
am doar un absent la un seminarul de la matematica...

dar mai important ca orice...a disparut acea "flame" cu privire la stiinta
calculatoarelor...

sunt putin deprimat...

Dar imi iubesc meseria...

Dumnezeu sa aiba mila de mine!

Off...

2006-10-31T05:46:00.000-08:00

Vorba unui prieten..."Grea viata"

Imi place facultatea, dar exista inconveniente...

Ma gandesc uneori... ce o sa fac dupa facultate...am sa urmez un master... sau
am sa am angajez in industria de dezvoltare si cercetare softeware...nu stiu...

ce stiu e ca as vrea acuma sa lucrez pe diferite site-uri....
Dar am teme ...am de invatat...stiinta este ceva ce atrage...

apoi mai sunt si jocurile...si daca ma prinde mania jocurilor...greu scap...
si scap, dar voi suporta consecintele...

Dumnezeu cu mila!

Dupa 3 saptamani

2006-10-24T00:07:00.000-07:00

Ce pot sa zic...facultatea e faina...

Algoritmi si programare e materia favorita....

Abia astept cursurile viitoare...gen Programarea orientata obiect...

Sa ma prezint

2006-10-23T06:02:00.000-07:00

Imi cer iertare...am uitat sa ma prezint

Sunt Paul Guralivu,20, sunt student la facultatea de informatica...

Tocmai am absolvit Colegiul Richard Wurmbrand Iasi...

Am venit la informatica...pentru ca asta am vrut sa fac din clasa a 2a...
atunci tatal meu mi-a pus in fata un calcultator....
si a fost dragoste la prima vedere...
de-a lungul timpului m-am orientat spre programare...

Dupa 2 saptamani

2006-10-15T02:29:00.000-07:00

Iubesc facultatea....

M-am intalnit cu fostii mei colegi din liceu....
fiecare a povestit cum a fost..ca prea a fost plictisitor....
ca prea a fost infricosator...

pentru mine:sunt in paradis....

Paul Guralivu, facultatea de informatica....viata frate

Prima saptamana la facultate-test drive-ul jucariei

2006-10-10T00:16:00.000-07:00

Bine ati venit la "Jurnalul unui copilas despre jucaria lui"...

Prima saptamana a fost cea mai interesanta...stiti voi...cunoasterea colegilor...
a profesorilor...stiti voi....cum va numiti? de unde veniti? ai facut sau nu

Si uzualele raspunsuri
Ma numesc.... si Vin de la ....