Socket Programming- TCP server

11 12 2007

A Server Side TCP implementation c code 1.0

int main(void)
int sockfd;
struct sockaddr_in my_addr; // my address information
struct sockaddr_in their_addr; // connector’s address information
int addr_len, numbytes;
char buf[MAXBUFLEN];

if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {

//2. Set
my_addr.sin_family = AF_INET; // host byte order
my_addr.sin_port = htons(MYPORT); // short, network byte order
my_addr.sin_addr.s_addr = INADDR_ANY; // automatically fill with my IP
memset(&(my_addr.sin_zero), ”,8);

//3. Bind
if (bind(sockfd, (struct sockaddr *)&my_addr,sizeof(struct sockaddr)) == -1) {

int status = listen(sockfd, 5);

//5.Accepting Connections

socklen_t sin_size = sizeof(struct sockaddr);
int ctr=0;

printf(“waiting for clients\n”);
int new_fd = accept(sockfd,(struct sockaddr*)&their_addr,&sin_size);
pthread_t t;

//Receiving Clients and handling them


//Closing Socket

return 0;




11 12 2007


Just as enumerations group constants together, so arrays can be thought of as grouping variables together. There’s a lot of support for arrays built into C#, and we’ll take a look at it in Chapter 6. As you know, arrays store data values by index. In C#, arrays are reference types, so you can create a new array with the new operator. You declare an array as type[], where type is the data type of each element. For example, here’s how to declare an array of five integer elements:

int[] array1 = new int[5];

These elements can be addressed with index values 0 to 4, as array1[0], array1[1], up to array1[4]. You can see this at work in Listing 1.5, where we’ve created a C# array, placed data in one of its elements, and displayed that data.


In C#, you need to declare arrays as type[] name; the optional C++-style declaration type name[]; isn’t available in C#.

Listing 1.5 Using an Array (ch01_05.cs)
class ch01_05
  static void Main()
    int[] array1 = new int[5];
    array1[0] = 1;
    System.Console.WriteLine("The first element holds {0}.", array1[0]);

You can also initialize each element in an array when you declare the array by assigning it a list of values

int[] array1 = {1, 2, 3, 4, 5};
array1[0] = 1;
System.Console.WriteLine("The first element holds {0}.", array1[0]);

One common use of arrays is for reading arguments typed on the command line when your code is invoked. If you declare an array of type string[] in the parentheses following the Main method, C# will fill that array with any command-line arguments. You can see an example in Listing 1.6, set up to take exactly four command-line arguments (any more or any less will cause an error in this example).

Listing 1.6 Using an Array (ch01_06.cs)
class ch01_06
  static void Main(string[] args)
    System.Console.WriteLine("You entered: {0} {1} {2} {3}.",
      args[0], args[1], args[2], args[3]);

Here’s what you see when you run this example and type the command-line arguments "Now is the time" into this code:

C:\>ch01_06 Now is the time
You entered: Now is the time.

BOOK  : Microsoft® Visual C#® .NET 2003 Kick Start

Microsoft® Visual C#® .NET 2003 Kick Start

Enumerations, c#

11 12 2007


Enumerations are an alternative to constants, and provide a way of grouping constants together logically. For example, say you’re using a lot of constants like this:

const int Sunday = 1;
const int Monday = 2;
const int Tuesday = 3;
const int Wednesday = 4;
const int Thursday = 5;
const int Friday = 6;
const int Saturday = 7;
System.Console.WriteLine("Sunday is day {0}", Sunday);

This code will give you this output:

Sunday is day 1

However, all the constants you’ve created can be put into an enumeration, which groups them together logically. Here’s how you create an enumeration, using the enum statement:

[attributes] [modifiers] enum identifier [:base-type] {enumerator-list};

Here are the parts of this statement:

  • attributes (optional)— Holds optional declarative meta-information.

  • modifiers (optional)— Optional modifiers that include the new modifier and one of the four access modifiers like public and private.

  • identifier The enumeration name.

  • base-type (Optional)— The underlying type that specifies the storage allocated for each enumerator. It can be any of the integral types except char. The default is int.

  • enumerator-list The enumerators’ identifiers separated by commas, optionally including a value assignment.

Enumerations act like groups of constants, which can be any of the built-in signed or unsigned integer types (such as int, Byte, or UInt64, but not char). You can see an example in ch01_04.cs, in Listing 1.4, which declares an enumeration named Days (unless you declare a type like this, enum Days :uint {...}, the underlying type used for the constant in enumerations is int). (Note that the values in that example ascend smoothly from 1–7, but enumeration values can take any values consistent with their underlying type.)

Listing 1.4 Using an Enumeration (ch01_04.cs)
class ch01_04
  enum Days
    Sunday = 1,
    Monday = 2,
    Tuesday = 3,
    Wednesday = 4,
    Thursday = 5,
    Friday = 6,
    Saturday = 7,

  static void Main()
    System.Console.WriteLine("Sunday is day {0}", (int) Days.Sunday);

The code in Listing 1.4 will also give you this output:

Sunday is day 1

Note that we specify the type for constants in the Days enumeration by prefacing them with the cast (int), which casts the member of the enumeration to its underlying type:

System.Console.WriteLine("Sunday is day {0}", (int) Days.Sunday);

We’ll cover casts in a few pages; the upshot is that if you omit that cast, the value of Days.Sunday would be its symbolic name, “Sunday”, the value of Days.Monday would be “Monday” and so on, not the integers 1, 2, and so on. That’s because in C#, enumerations are formal data types, which means you have to convert them to their underlying types if you want to access the values each enumeration member stands for.

From : Microsoft® Visual C#® .NET 2003 Kick Start