ccplusplus.com: September 2011

Friday, September 30, 2011

struct timeval example

struct timeval example: ccplusplus.com

/***********************************************************************
 * File     :   struct-timeval.c
 * Author   :   Saurabh Gupta
 * Desc     :   C Program to demonstrate the struct timeval usage
 *              struct timeval in c
 *              struct timeval linux
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   PM 11:00 30 September 2011
 * Note     :   review the time functions of time.h
 ************************************************************************/
 #include <sys/time.h>
 #include <stdio.h>

int main () {
    struct timeval tim;
    gettimeofday(&tim, NULL);
    double dTime1 = tim.tv_sec+(tim.tv_usec/1000000.0);
    gettimeofday(&tim, NULL);
    double dTime2 = tim.tv_sec+(tim.tv_usec/1000000.0);
    printf("%.6lf seconds elapsed until you will execute the program and see the result !!!\n", dTime2 - dTime1);
 return 0;
 }
/*
 * OUTPUT
 *
 [sgupta@rhel55x86 c]$ gcc struct-timeval.c -o struct-timeval
 [sgupta@rhel55x86 c]$ ./struct-timeval
 0.000002 seconds elapsed until you will execute the program and see the result !!!
 [sgupta@rhel55x86 c]$
 */

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See Also:
-----------------------------------------------------------------

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Blocking Socket

Blocking Socket Calls

A blocking socket will not return control until it has sent (or received) some or all data specified for the operation. It is normal for a blocking socket not to send all data. The application must check the return value to determine how many bytes have been sent or received and it must resend any data not already processed. It also may cause problems if a socket continues to listen: a program may hang as the socket waits for data that may never arrive. When using blocking sockets, special consideration should be given to accept() as it may still block after indicating readability if a client disconnects during the connection phase.

Essentially, all socket calls are blocking in nature. In other words, they do not return control to the calling code until they complete. Ordinarily, this wouldn't matter, except that in network programming in general, and socket programming in particular, most operations fall into one of two categories:

1. they take time to complete

2. they rely on a third party to complete

For example, the accept function call will block until there is a connection available to be accepted. While blocked, the call will not return, and subsequently, no more processing can take place, which is especially dangerous in a single threaded application.

non blocking socket

Setting a socket to be 'non-blocking' simply means that the library is instructed not to block when it is called. So, if accept is called on a socket, and there are no connections pending, rather than waiting for one, control will be returned to the calling block. To set a non-blocking socket, the ioctlsocket function is used, specifying FIONBIO as the parameter, and 1 as the argument.

Thursday, September 29, 2011

socket essential functions

Socket-Specific
Functions

socketpair(2)

#include
<sys/types.h>

#include
<sys/socket.h>

int
socketpair(int domain, int type, int protocol, int sv[2]);

socket(2)

#include
    <sys/types.h>

#include
    <sys/socket.h>

int socket(int
domain, int type, int protocol);

bind(2)

#include
    <sys/types.h>

#include
    <sys/socket.h>

int bind(int
sockfd, struct sockaddr *my_addr, int addrlen);

connect(2)

#include
    <sys/types.h>

#include
    <sys/socket.h>

int connect(int
sockfd, struct sockaddr *serv_addr, int addrlen);

listen(2)

#include
    <sys/socket.h>

int listen(int s,
int backlog);

accept(2)

#include
    <sys/types.h>

#include
    <sys/socket.h>

int accept(int s,
struct sockaddr *addr, int *addrlen);

convert miles to Centimeter

/***********************************************************************
 * File     :   distance-converter.c
 * Author   :   Saurabh Gupta
 * Desc     :   c program to convert miles to Centimeter
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   AM 08:25 29 September 2011
 * Note     :   optimize the code remove the function call
 ************************************************************************/
#include <stdio.h>
/*
 * local function signatures
 */
 void MilesToAll (double x);
/*
 * global variables
 */
 double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
 
 int main(){
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
    printf ("XXXXXXXX                Distance Converter               XXXXXX\n");
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n"); 
	int nLoop = 1;
	int nDistanceChoice;
    // double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
	while(nLoop == 1){
		printf("\nPlease choose a conversion:\n"
		       "1: Miles to Kilometer\n"
		       "2: Miles to Meter\n"
		       "3: Miles to Feet\n"
               "4: Miles to Inches\n"
               "5: Miles to Centimeter\n"
               "6: Exit Program\n");
               
		scanf("%i", &nDistanceChoice);
		switch (nDistanceChoice){
			case 1:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf kilometers\nXXXX\n", dMiles, dKilometer);
				break;
			case 2:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf Meter\nXXXX\n", dMiles, dMeter);
				break;
            case 3:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Feet\nXXXX\n", dMiles, dFeet);
                break;
            case 4:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Inches\nXXXX\n", dMiles, dInche);
                break;
            case 5:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Centimeter\nXXXX\n", dMiles, dCentiMeter);
                break;
            case 6:
				nLoop = 0;
				break;
			default:
				printf("Invalid Entry, please try again.");
				break;
		}
	}
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
	return 0;
 }

/*
 * conversion function
 */
 void MilesToAll (double x) {
    dKilometer = dMiles * 1.609344;
    dMeter = dKilometer*1000;          
    dCentiMeter = dMeter*100;       
    dInche = dCentiMeter/2.54;
    dFeet = dInche/12;
 }
/*
 * OUTPUT
 *
[sgupta@rhel54x64 distance-conversion]$ gcc distance-converter.c -o distance-converter
[sgupta@rhel54x64 distance-conversion]$ ./distance-converter
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXX                Distance Converter               XXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

Please choose a conversion:
1: Miles to Kilometer
2: Miles to Meter
3: Miles to Feet
4: Miles to Inches
5: Miles to Centimeter
6: Exit Program
1
Enter the number of Miles : 15
XXXX
15.00 Miles = 24.14 kilometers
XXXX

Please choose a conversion:
1: Miles to Kilometer
2: Miles to Meter
3: Miles to Feet
4: Miles to Inches
5: Miles to Centimeter
6: Exit Program
2
Enter the number of Miles : 10
XXXX
10.00 Miles = 16093.44 Meter
XXXX

Please choose a conversion:
1: Miles to Kilometer
2: Miles to Meter
3: Miles to Feet
4: Miles to Inches
5: Miles to Centimeter
6: Exit Program
3
Enter the number of Miles : 20
XXXX
20.00 Miles = 105600.00 Feet
XXXX

Please choose a conversion:
1: Miles to Kilometer
2: Miles to Meter
3: Miles to Feet
4: Miles to Inches
5: Miles to Centimeter
6: Exit Program
4
Enter the number of Miles : 30
XXXX
30.00 Miles = 1900800.00 Inches
XXXX

Please choose a conversion:
1: Miles to Kilometer
2: Miles to Meter
3: Miles to Feet
4: Miles to Inches
5: Miles to Centimeter
6: Exit Program
5
Enter the number of Miles : 50
XXXX
50.00 Miles = 8046720.00 Centimeter
XXXX

Please choose a conversion:
1: Miles to Kilometer
2: Miles to Meter
3: Miles to Feet
4: Miles to Inches
5: Miles to Centimeter
6: Exit Program
6
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
[sgupta@rhel54x64 distance-conversion]$
 */

convert miles to Inches

/***********************************************************************
 * File     :   distance-converter.c
 * Author   :   Saurabh Gupta
 * Desc     :   c program to convert miles to Inches
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   AM 08:25 29 September 2011
 * Note     :   optimize the code remove the function call
 ************************************************************************/
#include <stdio.h>
/*
 * local function signatures
 */
 void MilesToAll (double x);
/*
 * global variables
 */
 double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
 
 int main(){
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
    printf ("XXXXXXXX                Distance Converter               XXXXXX\n");
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n"); 
	int nLoop = 1;
	int nDistanceChoice;
    // double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
	while(nLoop == 1){
		printf("\nPlease choose a conversion:\n"
		       "1: Miles to Kilometer\n"
		       "2: Miles to Meter\n"
		       "3: Miles to Feet\n"
               "4: Miles to Inches\n"
               "5: Miles to Centimeter\n"
               "6: Exit Program\n");
               
		scanf("%i", &nDistanceChoice);
		switch (nDistanceChoice){
			case 1:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf kilometers\nXXXX\n", dMiles, dKilometer);
				break;
			case 2:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf Meter\nXXXX\n", dMiles, dMeter);
				break;
            case 3:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Feet\nXXXX\n", dMiles, dFeet);
                break;
            case 4:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Inches\nXXXX\n", dMiles, dInche);
                break;
            case 5:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Centimeter\nXXXX\n", dMiles, dCentiMeter);
                break;
            case 6:
				nLoop = 0;
				break;
			default:
				printf("Invalid Entry, please try again.");
				break;
		}
	}
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
	return 0;
 }

convert miles to feets

/***********************************************************************
 * File     :   distance-converter.c
 * Author   :   Saurabh Gupta
 * Desc     :   c program to convert miles to feets
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   AM 08:25 29 September 2011
 * Note     :   optimize the code remove the function call
 ************************************************************************/
#include <stdio.h>
/*
 * local function signatures
 */
 void MilesToAll (double x);
/*
 * global variables
 */
 double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
 
 int main(){
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
    printf ("XXXXXXXX                Distance Converter               XXXXXX\n");
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n"); 
	int nLoop = 1;
	int nDistanceChoice;
    // double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
	while(nLoop == 1){
		printf("\nPlease choose a conversion:\n"
		       "1: Miles to Kilometer\n"
		       "2: Miles to Meter\n"
		       "3: Miles to Feet\n"
               "4: Miles to Inches\n"
               "5: Miles to Centimeter\n"
               "6: Exit Program\n");
               
		scanf("%i", &nDistanceChoice);
		switch (nDistanceChoice){
			case 1:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf kilometers\nXXXX\n", dMiles, dKilometer);
				break;
			case 2:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf Meter\nXXXX\n", dMiles, dMeter);
				break;
            case 3:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Feet\nXXXX\n", dMiles, dFeet);
                break;
            case 4:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Inches\nXXXX\n", dMiles, dInche);
                break;
            case 5:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Centimeter\nXXXX\n", dMiles, dCentiMeter);
                break;
            case 6:
				nLoop = 0;
				break;
			default:
				printf("Invalid Entry, please try again.");
				break;
		}
	}
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
	return 0;
 }

convert miles to meters

/***********************************************************************
 * File     :   distance-converter.c
 * Author   :   Saurabh Gupta
 * Desc     :   c program to convert miles to meters
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   AM 08:25 29 September 2011
 * Note     :   optimize the code remove the function call
 ************************************************************************/
#include <stdio.h>
/*
 * local function signatures
 */
 void MilesToAll (double x);
/*
 * global variables
 */
 double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
 
 int main(){
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
    printf ("XXXXXXXX                Distance Converter               XXXXXX\n");
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n"); 
	int nLoop = 1;
	int nDistanceChoice;
    // double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
	while(nLoop == 1){
		printf("\nPlease choose a conversion:\n"
		       "1: Miles to Kilometer\n"
		       "2: Miles to Meter\n"
		       "3: Miles to Feet\n"
               "4: Miles to Inches\n"
               "5: Miles to Centimeter\n"
               "6: Exit Program\n");
               
		scanf("%i", &nDistanceChoice);
		switch (nDistanceChoice){
			case 1:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf kilometers\nXXXX\n", dMiles, dKilometer);
				break;
			case 2:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf Meter\nXXXX\n", dMiles, dMeter);
				break;
            case 3:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Feet\nXXXX\n", dMiles, dFeet);
                break;
            case 4:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Inches\nXXXX\n", dMiles, dInche);
                break;
            case 5:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Centimeter\nXXXX\n", dMiles, dCentiMeter);
                break;
            case 6:
				nLoop = 0;
				break;
			default:
				printf("Invalid Entry, please try again.");
				break;
		}
	}
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
	return 0;
 }

convert miles to kilometers

/***********************************************************************
 * File     :   distance-converter.c
 * Author   :   Saurabh Gupta
 * Desc     :   c program to convert miles to kilometers
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   AM 08:25 29 September 2011
 * Note     :   optimize the code remove the function call
 ************************************************************************/
#include <stdio.h>
/*
 * local function signatures
 */
 void MilesToAll (double x);
/*
 * global variables
 */
 double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
 
 int main(){
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
    printf ("XXXXXXXX                Distance Converter               XXXXXX\n");
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n"); 
	int nLoop = 1;
	int nDistanceChoice;
    // double dMiles, dKilometer, dMeter, dCentiMeter, dInche, dFeet;
	while(nLoop == 1){
		printf("\nPlease choose a conversion:\n"
		       "1: Miles to Kilometer\n"
		       "2: Miles to Meter\n"
		       "3: Miles to Feet\n"
               "4: Miles to Inches\n"
               "5: Miles to Centimeter\n"
               "6: Exit Program\n");
               
		scanf("%i", &nDistanceChoice);
		switch (nDistanceChoice){
			case 1:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf kilometers\nXXXX\n", dMiles, dKilometer);
				break;
			case 2:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
				printf("XXXX\n%.2lf Miles = %.2lf Meter\nXXXX\n", dMiles, dMeter);
				break;
            case 3:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Feet\nXXXX\n", dMiles, dFeet);
                break;
            case 4:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Inches\nXXXX\n", dMiles, dInche);
                break;
            case 5:
				printf("Enter the number of Miles : ");
				scanf("%lf", &dMiles);
                MilesToAll(dMiles);
                printf("XXXX\n%.2lf Miles = %.2lf Centimeter\nXXXX\n", dMiles, dCentiMeter);
                break;
            case 6:
				nLoop = 0;
				break;
			default:
				printf("Invalid Entry, please try again.");
				break;
		}
	}
    printf ("XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX\n");
	return 0;
 }

Wednesday, September 28, 2011

C++ Project : C++ Tutor

C++ Tutor

Version 1.0.0

Introduction

This introductory chapter provides an overview C++ Tutor, along with the hardware, software required for using it and the platforms on which it is supported.

About C++ Tutor

This utility is a fun utility that is designed to learn C++ concepts in an interactive way like you are seeing in any of the good c++ websites. This utility explains all the C++ concepts with the example code also. These all come with user friendly option that are displayed as an option menu. See the screenshot below for that.

C++ Tutor Supported Platforms

S.No	Version	Platform
1	1.0.0	All the Linux Systems like Red Hat based
2	1.0.0	All the UNIX systems like AIX, Solaris
3	1.0.0	Windows systems.

Note: The C++ Tutor supported platforms have no limit, all the required dependencies are shipped with the C++ Tutor. The platforms mentioned above are tested for this current release, and later with the new release they can be increased.

C++ Tutor Software Details

C++ Tutor is written and developed using C/C++. It has all the ANSI standards that are applicable to C++.
It is compiled under Linux with gnu GCC compiler version 4.1.2.
Under windows it is build using Visual Studio 2005.

C++ Tutor Hardware requirement

C++ Tutor has a very less requirement. Under Linux it can run with any lowest combination. Under windows it can run with a minimum that Windows function properly.

C++ Tutor Features

A Sample run is shown below. This is the help page design to see all the various tasks that this utility can do.

=====================================================================================

A development version of C++ tutor:

On expanding a menu:

Note: This is just a under development version. There are lots of the UI enhancement and additions are going on.

========================================================================================

Benefits of using C++ Tutor

C++ Tutor is a learning utility that can be modified by you. It has option that you can use to modify the tutor. Like if you want to add something your own concepts.

You can use this to learn all the C++ concepts, and carry with your email to any place in the word.

C++ Tutor Contact Support

You can reach for on demand demo and other related enquires @ projects@ccplusplus.com

Tuesday, September 27, 2011

getsockname example c

/***********************************************************************
 * File     :   getsockname.c
 * Author   :   Saurabh Gupta
 * Desc     :   getsockname example linux
 * Source   :   http://saurabhgupta0527.blogspot.com/2011/07/socket.html
 * Created  :   PM 09:32 27 September 2011
 * Note     :   
 ***********************************************************************/
 #include <stdio.h>
 #include <unistd.h>
 #include <stdlib.h>
 #include <errno.h>
 #include <string.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/socket.h>
 #include <sys/un.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>

/*
 * This saves lines of code later:
 */

static void displayError(const char *on_what) {
    perror(on_what); /* Report error */
    exit(1);         /* Exit Program */
 }

/*
 * This function accepts as input a socket
 * for which a socket address must be
 * determined for it. Then the address
 * is converted into a string and returned.
 *
 * If an error occurs, NULL is returned.
 */

char * sock_addr(int s,char *buf,size_t bufsiz) {
    int z;         /* Status return code */
    struct sockaddr_in adr_inet;/* AF_INET */
    int len_inet;  /* length */
/*
 * Obtain the address of the socket:
 */
    len_inet = sizeof adr_inet;
    z = getsockname(s, (struct sockaddr *)&adr_inet, &len_inet);
    if ( z == -1 ) {
       return NULL; /* Failed */
    }
/*
 * Convert address into a string
 * form that can be displayed:
 */
    snprintf(buf,bufsiz, "%s:%u",
    inet_ntoa(adr_inet.sin_addr),
    (unsigned)ntohs(adr_inet.sin_port));
    return buf;
 }

/*
 * Main Program:
 */

int  main(int argc,char **argv,char **envp) {
    int z; /* Status return code */
    int sck_inet; /* Socket */
    struct sockaddr_in adr_inet;/* AF_INET */
    int len_inet; /* length */
    char buf[64]; /* Work buffer */
/*
 * Create an IPv4 Internet Socket:
 */
    sck_inet = socket(AF_INET,SOCK_STREAM,0);
    if ( sck_inet == -1 ) {
       displayError("socket()");
    }

/*
 * Create an AF_INET address:
 */
    memset(&adr_inet,0,sizeof adr_inet);
    adr_inet.sin_family = AF_INET;
    adr_inet.sin_port = htons(9000);
    inet_aton ("127.0.0.24",&adr_inet.sin_addr);
    len_inet = sizeof adr_inet;

/*
 * Now bind the address to the socket:
 */
    z = bind(sck_inet,
    (struct sockaddr *)&adr_inet,
    len_inet);
    if ( z == -1 ) {
       displayError("bind()");
    }

/*
 * Now test our sock_addr() function:
 */

if ( !sock_addr(sck_inet,buf,sizeof buf)) {
       displayError("sock_addr()");
    }

printf("Address is'%s'\n" ,buf);
    close(sck_inet);
    return 0;
 }

/*
 * OUTPUT
 *
 [sgupta@rhel55x86 getsockname]$ gcc getsockname.c -o getsockname
 [sgupta@rhel55x86 getsockname]$ ./getsockname
  Address is'127.0.0.24:9000'
 [sgupta@rhel55x86 getsockname]$
 */

Monday, September 26, 2011

using struct tm in c

/***********************************************************************
 * File     :   using-struct-tm.c
 * Author   :   Saurabh Gupta
 * Desc     :   using struct tm
 * Source   :   http://saurabhgupta0527.blogspot.com/p/c.html
 * Created  :   PM 10:12 26 September 2011
 * Note     :   see the struct tm
 ***********************************************************************/
 #include <stdio.h>
 #include <time.h>

int main () {
      time_t rawtime;
      struct tm * stTimeInfo;
      int nYear, nMonth, nDay;
      char * weekday[] = { "Sunday",
                           "Monday",
                           "Tuesday", 
                           "Wednesday",
                           "Thursday",
                           "Friday", 
                           "Saturday"};
     /*
      * take the user date
      */
      printf ("Enter Year: ");
      scanf  ("%d",&nYear);
      printf ("Enter Month: "); 
      scanf  ("%d",&nMonth);
      printf ("Enter Day: "); 
      scanf  ("%d",&nDay);

/*
      * get current stTimeInfo and modify it to the user's choice 
      */
      time ( &rawtime );
      stTimeInfo = localtime ( &rawtime );
      stTimeInfo->tm_year = nYear - 1900;
      stTimeInfo->tm_mon = nMonth - 1;
      stTimeInfo->tm_mday = nDay;

/*
      * call mktime: stTimeInfo->tm_wday will be set 
      */
      mktime ( stTimeInfo );
      printf ("Entered Day is a %s.\n", weekday[stTimeInfo->tm_wday]);
      return 0;
 }
/*
 * OUTPUT
 *
 [sgupta@rhel55x86 c]$ gcc using-struct-tm.c -o using-struct-tm
 [sgupta@rhel55x86 c]$ ./using-struct-tm
 Enter Year: 2011
 Enter Month: 9
 Enter Day: 26
 Entered Day is a Monday.
 [sgupta@rhel55x86 c]$
 */